Add opengraph tags to podcast pages

[nomeata]

It annoyed me that linking to the podcast pages on social media, e.g. on https://discourse.haskell.org/t/haskell-interlude-episode-22-alejandro-russo/5886, does not produce a nice preview box. This PR should fix this, by including the opengraph title and description tags.

The description is taken from the first paragraph of the source markdown file.

[nomeata]

Here is the effect:

~/projekte/programming/haskell/haskellfoundation.github.io $ grep og:descrip _site/**/*.html
_site/careers/devops.html:  <meta property="og:description" content="The Haskell Foundation is looking for a DevOps engineer to take the Haskell ecosystem to the next level of stability, reliability, and performance.
_site/podcast/0/index.html:  <meta property="og:description" content="We are starting a new Haskell-focused podcast where we interview guests from the Haskell community. The hosts are Niki Vazou, Joachim Breitner, Andres Löh, Alejandro Serrano and Wouter Swierstra. In this teaser episode, we introduce ourselves.
_site/podcast/10/index.html:  <meta property="og:description" content="Nadia Polikarpova is interviewed by Alejandro Serrano and Niki Vazou. Nadia is an assistant professor at UCSD, where she works on improving how we write programs. They talk about some of her projects, like Hoogle+ and Synquid, and how she approaches teaching about these topics.
_site/podcast/11/index.html:  <meta property="og:description" content="Simon Peyton Jones is interviewed by Andres Löh and Joachim Breitner. Simon is the creator of Haskell and in this episode he talks about his new position at Epic, the origins of Haskell and why &quot;it feels right&quot;, and the (extra)ordinary Haskell programmers.
_site/podcast/12/index.html:  <meta property="og:description" content="Gergő Érdi is interviewed by Wouter Swierstra and Andres Löh. Gergő has an interesting path into Haskell taking many twists and turns. This episode discusses about these twists and Gergő's recent book on implementing retro computers using Haskell.
_site/podcast/13/index.html:  <meta property="og:description" content="David Christiansen is interviewed by Alejandro Serrano and Wouter Swierstra. They talk about many functional programming things, from Idris to Racket and of course Haskell and David's new role as the executive director of Haskell Foundation.
_site/podcast/14/index.html:  <meta property="og:description" content="Ryan Trinkle is interviewed by Joachim Breitner and Niki Vazou. Ryan Trinkle has co-founded Obsidian Systems, a company that not just uses Haskell but even more exotic tech that as Functional Reactive Programming (FRP) and Nix. Ryan shed some light on the business side of Haskell and we get to hear that hiring for Haskell is actually excellent.
_site/podcast/15/index.html:  <meta property="og:description" content="Facundo Dominguez is interviewed by Niki Vazou and Joachim Breitner. Facundo
_site/podcast/16/index.html:  <meta property="og:description" content="Oskar Wickström is interviewed by Wouter Swierstra and Alejandro Serrano, he
_site/podcast/17/index.html:  <meta property="og:description" content="Ningning Xie is interviewed by Niki Vazou and Andres Loh. Ningning first contributed to GHC at her Google summer of code project with a very ambitious goal of implementing the whole dependent Haskell. Also later she fixed several ghc bugs and worked on Koka's Algebraic effects. Her future hope and advice is to use programming language concepts on real-word problems.
_site/podcast/18/index.html:  <meta property="og:description" content="In this episode Matthias Pall Gissurarson &amp; Jimmy Koppel are interviewed by Wouter Swierstra and Niki Vazou. They talk about program synthesis, typed holes, program repair, and generating properties using a new technique called ECTAs.
_site/podcast/19/index.html:  <meta property="og:description" content="In this episode Marc Scholten is interviewed by Andres Löh and Joachim
_site/podcast/1/index.html:  <meta property="og:description" content="The guest of our first regular episode is Emily Pillmore, CTO of the Haskell
_site/podcast/20/index.html:  <meta property="og:description" content="In this episode Jesper Cockx, one of the main Agda developers, is interviewed by Niki Vazou and Matthias Pall. They talk about how to explain dependent types to one's father, how Agda's automation and proof search work, and how Agda can be used to verify Haskell code bases.
_site/podcast/21/index.html:  <meta property="og:description" content="In this episode Matthías Páll and Andres Löh talk with Andrey Mokhov.
_site/podcast/22/index.html:  <meta property="og:description" content="In this episode Andres Löh and Niki Vazou talk with Alejandro Russo. Alejandro is a professor at Chalmers University in Gothenburg Sweden, he is an enthusiastic functional programmer as well as a researcher in the fields of security and privacy. He talks about the unique strengths Haskell has in these areas and how to move research ideas into industry.
_site/podcast/2/index.html:  <meta property="og:description" content="The guest in our second episode is Lennart Augustsson. The hosts are Wouter Swierstra and Niki Vazou. We talk about Lennart's long history with Haskell, about the various jobs he has had, all the compilers he has written, and about dependent types.
_site/podcast/3/index.html:  <meta property="og:description" content="Gabriella Gonzalez is interviewed by Joachim Breitner and Alejandro Serrano,
_site/podcast/4/index.html:  <meta property="og:description" content="Jasper Van der Jeugt is interviewed by Niki Vazou and Joachim Breitner.
_site/podcast/5/index.html:  <meta property="og:description" content="Chris Smith is interviewed by Joachim Breitner and Andres Löh. Chris is the author of the CodeWorld teaching tool and discusses why too much curry in the language can make error messages hard to digest and why a self respecting testing library certainly should be used to test itself.
_site/podcast/6/index.html:  <meta property="og:description" content="Graham Hutton is interviewed by Wouter Swierstra and Andres Löh. Graham is known for his work on Haskell both in research and teaching Haskell, and in particular his Haskell book. Graham will tell us a little bit about how his book came about and give us advice for how to write a book ourselves, but also look back on his experience using Haskell and teaching Haskell in the last thirty years, and tell us a little bit about how bad the compile times were for the very first versions of GHC.
_site/podcast/7/index.html:  <meta property="og:description" content="José Calderón is interviewed by Niki Vazou and Wouter Swierstra . José has been working on functional programming at Galois and University of Maryland. He tells us about his research background in many different continents, his experience with teaching compilers, the relation between music and functional programming and the &quot;Recursive Programming Techniques&quot; book that in the 1970s captured the essence of functional programming.
_site/podcast/8/index.html:  <meta property="og:description" content="Niki Vazou and Andres Löh are joined by guest Théophile Choutri (they/them), who
_site/podcast/9/index.html:  <meta property="og:description" content="Sebastian Graf is interviewed by Joachim Breitner and Alejandro Serrano. Sebastian is one of the most active contributors to GHC, and tells of this experience, from his very first commit to GHC to his current work on the pattern coverage checker and demand analyzer. He also gives us hints on how to reason about the strictness of Haskell programs.

[nomeata]

Thanks, looks much better on https://discourse.haskell.org/t/haskell-interlude-episode-22-alejandro-russo/5886

[nikivazou]

Indeed!!! Thanks!