pelican-quickstart: switch to jinja2

[ix5]

As per request by @justinmayer on issue #2000, to omit unused build targets and allow for more powerful templating.

• Use the jinja2 templating language for Makefile, fabfile,
  pelicanconf, publishconf, and develop-server.sh
• Add logic in pelican_quickstart.py
• Let jinja2 handle opening and reading template files
• Remove thus unused functions for string.Template

[ix5]

Do we really need to make flake8-import-order happy?
They say this about themselves:

This plugin is under somewhat active development and is heavily influenced by the personal preferences of the developers of cryptography. Expect seemingly random changes and configuration changes as we figure out how it should work.

[ix5]

Closing due to inactivity

[justinmayer]

Apologies, @ix5. It's been a busy year.

Any @getpelican/reviewers have a moment to review this pull request?

[iKevinY]

Apologies for the review delay, @ix5. I ran pelican-quickstart, and the generated Makefile and configuration files all look good! There are few changes that need to be pulled in (see merge conflicts), but other than that, this seems good to merge to me. 👍

[ix5]

Heh, I saw the growing backlog of issues and PRs, didn't want to keep it that way and closed this one.

Anyway, I've rebased off master, fixed conflicts, should be good to go. Travis gives the go-ahead as well.

Thanks for keeping this project running, @justinmayer, you're a treasure. And thank you @iKevinY as well!

[ix5]

Hey @iKevinY @justinmayer could you please merge this?

[justinmayer]

Many thanks, @ix5, for your contribution, kind words, and patience. And thanks to @iKevinY for reviewing!