Optionally support web+mastodon links

[rugk]

Test page/JSFiddle: https://jsfiddle.net/pvyoof6L/3/

Ref for implementation: https://github.com/tootsuite/mastodon/pull/4511

Previous discussion: https://github.com/rugk/mastodon-simplified-federation/issues/31

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TODO:

• [ ] add an option for all that (opt-out), because users may want to disable it in case they prefer a native Mastodon client instead
• [ ] redirect the follow me button as usual
• [ ] redirect the message button (hopefully Mastodons API is good for that)
• [ ] check out, whether an "interaction" button can be designed/used by webdevs in the same way (i.e. like "Interact with this toot!"), also redirect that obviously

[rugk]

AFAIK this was deprecated/removed in Mastodon, so it does not have a high priority… (Or maybe not?)

• [ ] needs research whether this is still implemented :astonished:

[saschanaz]

Dead indeed: https://github.com/mastodon/mastodon/pull/8127