Store tiles by component name and user

This way, when the user changes, the old tile is not just replaced in the
map, instead we keep it until it can be freed. This solves an issue of
active tiles not being able to be set into listening state after user
changing.

Test: atest TileServices
Test: manual, using sample tile service app
Fixes: 243902636
Change-Id: I57d08aec5c0b40f09f5bd763d63068aaea7ba450