[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>

templates/swagger/v1_json.tmpl

@@ -4966,6 +4966,48 @@
           }
         }
       },
+      "delete": {
+        "tags": [
+          "issue"
+        ],
+        "summary": "Delete an issue",
+        "operationId": "issueDelete",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "owner of the repo",
+            "name": "owner",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the repo",
+            "name": "repo",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "integer",
+            "format": "int64",
+            "description": "index of issue to delete",
+            "name": "index",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "204": {
+            "$ref": "#/responses/empty"
+          },
+          "403": {
+            "$ref": "#/responses/forbidden"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
+          }
+        }
+      },
       "patch": {
         "consumes": [
           "application/json"