Adds a CTA on the room list to view invites if there are any.
The invite list presents each invite with accept/decline buttons
and (for room invites) the sender details.
Fixes#102
The rustsdk library wasn't included in the gradle build because
it still used a groovy build file (and settings.gradle includes
projects based on `build.gradle.kts` existing).
Also reword the onboarding docs slightly to clarify the deps
that need changing