feat: add site_favicon.html helper to skeleton.html

[furkankurt]

Django Unfold doesn't have a favicon feature.
We had to override the whole skeleton.html template to add a favicon. Fixes #415

I have added a site_favicon.html file to the unfold/helpers directory, we can add all favicon types to the website.
Instead of overriding the skeleton.html, we will override just the site_favicon.html.

PS: I added example favicon links as template comments.

[furkankurt]

Thank you so much for closing my pull request without saying anything.
Very clever and good work @lukasvinclav 👏🏻

[lukasvinclav]

Ticket is still in backlog and it is pointing at this PR. Today I marked your ticket with a label "enhancement" and I was planning to start working on it very soon. Implementing favicon support is more complex than overriding simple template. It must have its own configuration in settings.py, docs, tests and support for various sizes so there is a lot of things to integrate.

I don't think there is place for such a reaction in open-source Django community which was always awesome. I'm just trying to ship new features and fixes as much as possible so there is no time to provide full fledged answers to everything in the repository. Thanks for understanding.

[furkankurt]

Ticket is still in backlog and it is pointing at this PR. Today I marked your ticket with a label "enhancement" and I was planning to start working on it very soon. Implementing favicon support is more complex than overriding simple template. It must have its own configuration in settings.py, docs, tests and support for various sizes so there is a lot of things to integrate.

I don't think there is place for such a reaction in open-source Django community which was always awesome. I'm just trying to ship new features and fixes as much as possible so there is no time to provide full fledged answers to everything in the repository. Thanks for understanding.

Thank you for your explanation :)