[API] Allow removing issues (#18879)

Add new feature to delete issues and pulls via API

Co-authored-by: fnetx <git@fralix.ovh>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Gusted <williamzijl7@hotmail.com>
Co-authored-by: 6543 <6543@obermui.de>

routers/api/v1/repo/issue.go

@@ -834,6 +834,52 @@ func EditIssue(ctx *context.APIContext) {
 	ctx.JSON(http.StatusCreated, convert.ToAPIIssue(issue))
 }
 
+func DeleteIssue(ctx *context.APIContext) {
+	// swagger:operation DELETE /repos/{owner}/{repo}/issues/{index} issue issueDelete
+	// ---
+	// summary: Delete an issue
+	// parameters:
+	// - name: owner
+	//   in: path
+	//   description: owner of the repo
+	//   type: string
+	//   required: true
+	// - name: repo
+	//   in: path
+	//   description: name of the repo
+	//   type: string
+	//   required: true
+	// - name: index
+	//   in: path
+	//   description: index of issue to delete
+	//   type: integer
+	//   format: int64
+	//   required: true
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+	//   "403":
+	//     "$ref": "#/responses/forbidden"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
+	issue, err := models.GetIssueByIndex(ctx.Repo.Repository.ID, ctx.ParamsInt64(":index"))
+	if err != nil {
+		if models.IsErrIssueNotExist(err) {
+			ctx.NotFound(err)
+		} else {
+			ctx.Error(http.StatusInternalServerError, "GetIssueByID", err)
+		}
+		return
+	}
+
+	if err = issue_service.DeleteIssue(ctx.User, ctx.Repo.GitRepo, issue); err != nil {
+		ctx.Error(http.StatusInternalServerError, "DeleteIssueByID", err)
+		return
+	}
+
+	ctx.Status(http.StatusNoContent)
+}
+
 // UpdateIssueDeadline updates an issue deadline
 func UpdateIssueDeadline(ctx *context.APIContext) {
 	// swagger:operation POST /repos/{owner}/{repo}/issues/{index}/deadline issue issueEditIssueDeadline