Change mastodon icon to font awesome

[Janfred]

I'm submitting a ..

• Bug Report
• Feature Request
• Code smell issue

Current behavior:
With #1839 osem has the possibility to link to mastodon. Currently the icon is not in font awesome, so a special font is embedded.

Expected correct behavior:
Once a mastodon icon is included in font awesome the code should be reworked to use the font awesome icon instead of the custom font.

Other information:
Font Awesome Issue: FortAwesome/Font-Awesome#10897
I'll submit a pull request once the icon is included in FontAwesome

[xuv]

If you wish, you can take a look at Fork Awesome, a fork of Font Awesome 4.7, that includes a lot of open source logos, and Mastodon in different flavors:

• https://forkawesome.github.io/Fork-Awesome/icon/mastodon/
• https://forkawesome.github.io/Fork-Awesome/icon/mastodon-alt/
• https://forkawesome.github.io/Fork-Awesome/icon/mastodon-square/

[Janfred]

The icon is available in FontAwesome 5.0.11 (See linked FontAwesome Issue in the initial post)

Anyway, the font-awesome-rails gem does not yet support the font-awesome 5.x versions, and maybe never will, since it requires a complete rewrite of the gem according to bokmann/font-awesome-rails#194

It might be a good idea to switch to direct font awesome, as suggested in bokmann/font-awesome-rails#194 (comment)