Hygiene: Refactor talk overlay

Change-Id: I24f605d5546d53c2184cdb56f9668081fc8917c9
Hygiene: Make add talk discussion a route.

Bug: 71076
Change-Id: I0ba931bfd20bb083c8f226f8f39ad711f6d88a2e
Merge "Hygiene: Refactor talk overlay"
Merge "Hygiene: Make add talk discussion a route."