* Alerting: modify table and accessors to limit org access appropriately
* Update migration to create multiple Alertmanager configs
* Apply suggestions from code review
Co-authored-by: gotjosh <josue@grafana.com>
* replace mg.ClearMigrationEntry()
mg.ClearMigrationEntry() would create a new session.
This commit introduces a new migration for clearing an entry from migration log for replacing mg.ClearMigrationEntry() so that all dashboard alert migration operations will run inside the same transaction.
It adds also `SkipMigrationLog()` in Migrator interface for skipping adding an entry in the migration_log.
Co-authored-by: gotjosh <josue@grafana.com>