Kanban colored boards (#16647)

Add a column Color in ProjectBoard and color picker in new / edit project board form.

routers/web/repo/projects.go

@@ -444,6 +444,7 @@ func AddBoardToProjectPost(ctx *context.Context) {
 	if err := models.NewProjectBoard(&models.ProjectBoard{
 		ProjectID: project.ID,
 		Title:     form.Title,
+		Color:     form.Color,
 		CreatorID: ctx.User.ID,
 	}); err != nil {
 		ctx.ServerError("NewProjectBoard", err)
@@ -513,6 +514,8 @@ func EditProjectBoard(ctx *context.Context) {
 		board.Title = form.Title
 	}
 
+	board.Color = form.Color
+
 	if form.Sorting != 0 {
 		board.Sorting = form.Sorting
 	}