* clean up and document integration test convention
* clarify integration test conventions
* clean up integration tests that don't follow convention
* mark testIntegration* functions as helpers to avoid confusion
* add: IsServiceAccount to SignedInUser and IsRealUser
* fix: linting error
* refactor: add function IsServiceAccountUser()
By adding the function IsServiceAccountUser() we use it to identify for
ServiceAccounts in the HasUniqueID() since caching is built up on having
a uniqueID, see comment: https://github.com/grafana/grafana/pull/58015#discussion_r1011361880
* chore: add alias for InitTestDB and Session
Adds an alias for the sqlstore InitTestDB and Session, and updates tests using these to reduce dependencies on the sqlstore.Store.
* next pass of removing sqlstore imports
* last little bit
* remove mockstore where possible
