Actions Runner rest api (#33873)

Implements runner apis based on
https://docs.github.com/en/rest/actions/self-hosted-runners?apiVersion=2022-11-28#list-self-hosted-runners-for-an-organization

- Add Post endpoints for registration-token, google/go-github revealed
this as problem
  - We should deprecate Get Endpoints, leaving them for compatibility
- Get endpoint of admin has api path /admin/runners/registration-token
that feels wrong, /admin/actions/runners/registration-token seems more
consistent with user/org/repo api
- Get Runner Api
- List Runner Api
- Delete Runner Api

- Tests admin / user / org / repo level endpoints

Related to #33750 (implements point 1 and 2)
Via needs discovered in #32461, this runner api is needed to allow
cleanup of runners that are deallocated without user interaction.

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/structs/repo_actions.go

@@ -133,3 +133,26 @@ type ActionWorkflowJob struct {
 	// swagger:strfmt date-time
 	CompletedAt time.Time `json:"completed_at,omitempty"`
 }
+
+// ActionRunnerLabel represents a Runner Label
+type ActionRunnerLabel struct {
+	ID   int64  `json:"id"`
+	Name string `json:"name"`
+	Type string `json:"type"`
+}
+
+// ActionRunner represents a Runner
+type ActionRunner struct {
+	ID        int64                `json:"id"`
+	Name      string               `json:"name"`
+	Status    string               `json:"status"`
+	Busy      bool                 `json:"busy"`
+	Ephemeral bool                 `json:"ephemeral"`
+	Labels    []*ActionRunnerLabel `json:"labels"`
+}
+
+// ActionRunnersResponse returns Runners
+type ActionRunnersResponse struct {
+	Entries    []*ActionRunner `json:"runners"`
+	TotalCount int64           `json:"total_count"`
+}