Add generic options to social networks

Before submitting an issue

Social Networks support specific tools such as Mastodon and WriteFreely, but do not offer the more generic "Fediverse".

I understand if this is on purpose, but it is difficult since there are effectively hundreds of fediverse web services, including Castopod.

Generic options with generic SVG icons, which I'd really appreciate:

• Chat
• Email
• Forum
• Fediverse

Thanks either way for considering! I am willing to put this together as a pull request, assuming you are open to accepting it.