Change username color in chat with power level color (#2282)

Change username color in chat with power level color (#2282)

* add active theme context

* add chroma js library

* add hook for accessible tag color

* disable reply user color - temporary

* render user color based on tag in room timeline

* remove default tag icons

* move accessible color function to plugins

* render user power color in reply

* increase username weight in timeline

* add default color for member power level tag

* show red slash in power color badge with no color

* show power level color in room input reply

* show power level username color in notifications

* show power level color in notification reply

* show power level color in message search

* render power level color in room pin menu

* add toggle for legacy username colors

* drop over saturation from member default color

* change border color of power color badge

* show legacy username color in direct rooms