Server info

Adding more supported XEPs to the list on the account details screen was discussed in #574. It was decided that a show more button would reduce clutter, but still allow people to get info about their server. Unfortunately, I forgot about it (and did something weird when rebasing from the looks of the issue) until just now.

I added a show more button, and added MaM and Blocking to the list (in the regular list and the show more list respectively).