Add message search functionality #192
Description
Add message search in rooms and across all rooms
Workaround
Since the Matrix Public Archive is indexed by Google, use that instead: site:archive.matrix.org foo
Concerns/notes
How do we handle cases where the homeserver doesn't have a portion of history backfilled yet where relevant results could be? Search really needs some form of indicating where its gaps are (related to MSC2871)
Searching across all rooms is dubious as gaps will be all over across many rooms at different points. How do we convey this information to the user that you may be missing some messages? How do we empower the user to fill in the gaps?
UI/UX
Search within a room can easily just be an option in the chat header when viewing a room
I'm not sure how we will expose search across all rooms and differentiate it from room search we currently have on the homepage.