Fix documentation issues

See merge request TransFem-org/Documentation!15

Reviewed-on: https://git.joinsharkey.org/Sharkey/Documentation/pulls/13

now everything should point to our forgejo; I also replaced the github
logo with the forgejo logo (copied from
https://git.joinsharkey.org/assets/img/logo.svg )

Reviewed-on: https://git.joinsharkey.org/Sharkey/Documentation/pulls/12

Reviewed-on: https://git.joinsharkey.org/Sharkey/Documentation/pulls/8

thanks Marie!

Reviewed-on: https://git.joinsharkey.org/Sharkey/Documentation/pulls/6


Reviewed-by: Marie <marie@kaifa.ch>

it can now handle any number of repos