feat: Allow toggle or custom dictionary for post/repost/etc. names #11

I think it's a bit funny to refer to posts on the network informally as "skeets", but personally I'm not necessarily a fan of them being used as the name in the client. Instead of reverting this (because I know opinions on this differ heavily and some people like this!), I feel like it would be beneficial to create either a toggle for this or a way to define custom terminology.

(just migrated from kitty/social.daniela.lol!)