docs: Update list of clients (#284)

docs: Update list of clients (#284)

In addition to making the page refer to Akkoma instead of Pleroma, I've
also removed clients that were not updated in a year or more and updated
links to websites and the contact links of authors.

Also removed language that suggested these clients are in any way
"officially supported".

Co-authored-by: Francis Dinh <normandy@biribiri.dev>
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/284
Co-authored-by: Norm <normandy@biribiri.dev>
Co-committed-by: Norm <normandy@biribiri.dev>