[Refactor] CombinedStatus and CommitStatus related functions & structs (#14026)

* RM unused struct

* rename (*CommitStatus) loadRepo() -> loadAttributes()

* move ToCommitStatus into its own file

* use CommitStatusState instead of StatusState

* move CombinedStatus convertion into convert package

* let models.GetLatestCommitStatus use repoID direct and accept ListOptions

* update swagger docs

* fix tests

* Fix swagger docs

* rm page

* fix swagger docs!!!

* return json null

* always return json

* rename api.Status to api.CommitStatus

* fix swagger docs

* sec swagger fix

routers/api/v1/swagger/repo.go

@@ -169,18 +169,18 @@ type swaggerResponsePullReviewCommentList struct {
 	Body []api.PullReviewComment `json:"body"`
 }
 
-// Status
-// swagger:response Status
+// CommitStatus
+// swagger:response CommitStatus
 type swaggerResponseStatus struct {
 	// in:body
-	Body api.Status `json:"body"`
+	Body api.CommitStatus `json:"body"`
 }
 
-// StatusList
-// swagger:response StatusList
-type swaggerResponseStatusList struct {
+// CommitStatusList
+// swagger:response CommitStatusList
+type swaggerResponseCommitStatusList struct {
 	// in:body
-	Body []api.Status `json:"body"`
+	Body []api.CommitStatus `json:"body"`
 }
 
 // WatchInfo
@@ -309,3 +309,10 @@ type swaggerLanguageStatistics struct {
 	// in: body
 	Body map[string]int64 `json:"body"`
 }
+
+// CombinedStatus
+// swagger:response CombinedStatus
+type swaggerCombinedStatus struct {
+	// in: body
+	Body api.CombinedStatus `json:"body"`
+}