Reduce unnecessary DB queries for Actions tasks (#25199)

Close #24544

Changes:

- Create `action_tasks_version` table to store the latest version of
each scope (global, org and repo).
- When a job with the status of `waiting` is created, the tasks version
of the scopes it belongs to will increase.
- When the status of a job already in the database is updated to
`waiting`, the tasks version of the scopes it belongs to will increase.
- On Gitea side, in `FeatchTask()`, will try to query the
`action_tasks_version` record of the scope of the runner that call
`FetchTask()`. If the record does not exist, will insert a row. Then,
Gitea will compare the version passed from runner to Gitea with the
version in database, if inconsistent, try pick task. Gitea always
returns the latest version from database to the runner.

Related:

- Protocol: https://gitea.com/gitea/actions-proto-def/pulls/10
- Runner: https://gitea.com/gitea/act_runner/pulls/219

models/migrations/migrations.go

@@ -515,6 +515,8 @@ var migrations = []Migration{
 	NewMigration("Alter Actions Artifact table", v1_21.AlterActionArtifactTable),
 	// v266 -> v267
 	NewMigration("Reduce commit status", v1_21.ReduceCommitStatus),
+	// v267 -> v268
+	NewMigration("Add action_tasks_version table", v1_21.CreateActionTasksVersionTable),
 }
 
 // GetCurrentDBVersion returns the current db version