Add API to get issue/pull comments and events (timeline) (#17403)

* Add API to get issue/pull comments and events (timeline)
Adds an API to get both comments and events in one endpoint with all required data.
Closes go-gitea/gitea#13250

* Fix swagger

* Don't show code comments (use review api instead)

* fmt

* Fix comment

* Time -> TrackedTime

* Use var directly

* Add logger

* Fix lint

* Fix test

* Add comments

* fmt

* [test] get issue directly by ID

* Update test

* Add description for changed refs

* Fix build issues + lint

* Fix build

* Use string enums

* Update swagger

* Support `page` and `limit` params

* fmt + swagger

* Use global slices

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

routers/api/v1/swagger/issue.go

@@ -36,6 +36,13 @@ type swaggerResponseCommentList struct {
 	Body []api.Comment `json:"body"`
 }
 
+// TimelineList
+// swagger:response TimelineList
+type swaggerResponseTimelineList struct {
+	// in:body
+	Body []api.TimelineComment `json:"body"`
+}
+
 // Label
 // swagger:response Label
 type swaggerResponseLabel struct {