Adjust mute duration options

[connyduck]

Based on this discussion: https://chaos.social/@RichiH/113876914927419020

Currently, we offer 5 minutes, 30 minutes, 1 hour, 6 hours, 1 day, 3 days, 7 days as possible duration when muting a users.

There are quite some short options that I don't think are necessary, and we are lacking a longer option.

Mastodon Web currently offers 6 hours, 24 hours, 7 days, 30 days.

I think we should change our options to be 1h, 6h, 24h, 1 week, 1 month, 6 months. A little bit more than Mastodon, not as many as we have now, but new longer options.

[Tak]

I think the current state is my fault, I just reused the poll durations 😅

[InsertUser]

A custom option with a date/time picker could be handy too if you are seeing lots of toots about a specific upcoming event and would like to do mutes that last until that is over.