Add Mastodon/Fediverse attribution meta tags

[goulvench]

Add <link rel="me"> and fediverse:creator meta.

See https://joinmastodon.org/verification and mastodon/mastodon#30398

To use, open site.metadata.yml and add mastodon username and server:

mastodon:
  username: handle
  server: mastodon.server

Generates:

<link rel="me" href="https://mastodon.server/@handle">
<meta name="fediverse:creator" content="@[email protected]">

[jaredcwhite]

This is awesome! Thanks 🙏🏻

[goulvench]

Glad you like it!
The test failures seem unrelated, but let me know if there's something I should do to push this forward.

[jaredcwhite]

@goulvench I think I can merge as-is, but would you be able to add a bit of documentation to the Readme? (sorry it's taken me a while to circle back around to this)

[goulvench]

Here's an update with a bit of documentation.

The "unescaped HTML in heredoc" warning tells me that I should replace this very basic implementation with mastodon_handle and mastodon_url methods in AuthorDrop. This would allow people to just drop @[email protected] into the site or page metadata, and be done with it, without wielding YAML…
I'll try and add this today.