Closes #5715: Login storage refactor
This refactor changes how (most) consumers are expected to interact with the logins storage. Instead of "locking"/"unlocking" the store whenever its needed, a connection to a storage layer is now cached on first access and re-used for subsequent operations. Various components relying on logins storage have been simplified.
components/service/sync-logins/src/main/java/mozilla/components/service/sync/logins/AsyncLoginsStorage.kt deleted 100644 → 0