Devtools

We should implement some developer tools, including [not exhaustive]:

• Showing State Events: Done in !622 (merged)
• Subpage for state keys
• Creating room State
• Sending custom timeline events
• Changing room State
• Creating Account data
• Changing account data
• Showing account data
• Showing room account data
• Showing events that are normally hidden (edits, reactions, poll answers, etc.)
• Sorting rooms in the RoomData room selector

Some more convenience things that would be cool:

• In the event source, show the human-readable time an event was sent
• In the state event view, show the human-readable time an event was sent
• In the user details dialog, show the datetime the user joined the room (this probably requires interating over the user's previous state events)