Implement DELETE /users/{user_id endpoint for APIv4 - rebase cleanup (#5307)

* added delete user endpoint

* added unit test for delete user endpoint

* added delete user driver

api4/user.go

@@ -21,6 +21,7 @@ func InitUser() {
 
 	BaseRoutes.User.Handle("", ApiSessionRequired(getUser)).Methods("GET")
 	BaseRoutes.User.Handle("", ApiSessionRequired(updateUser)).Methods("PUT")
+	BaseRoutes.User.Handle("", ApiSessionRequired(deleteUser)).Methods("DELETE")
 	BaseRoutes.User.Handle("/roles", ApiSessionRequired(updateUserRoles)).Methods("PUT")
 
 	BaseRoutes.Users.Handle("/login", ApiHandler(login)).Methods("POST")
@@ -192,6 +193,35 @@ func updateUser(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func deleteUser(c *Context, w http.ResponseWriter, r *http.Request){
+	c.RequireUserId()
+	if c.Err != nil {
+		return
+	}
+
+	userId := c.Params.UserId
+
+	if !app.SessionHasPermissionToUser(c.Session, userId) {
+		c.SetPermissionError(model.PERMISSION_EDIT_OTHER_USERS)
+		return
+	}
+	
+	var user *model.User
+	var err *model.AppError
+
+	if user, err = app.GetUser(userId); err != nil {
+		c.Err = err
+		return
+	}
+
+	if _, err := app.UpdateActive(user, false); err != nil {
+		c.Err = err
+		return	
+	}
+
+	ReturnStatusOK(w)
+}
+
 func updateUserRoles(c *Context, w http.ResponseWriter, r *http.Request) {
 	c.RequireUserId()
 	if c.Err != nil {