dashfolders: show folders use can save to in picker

Instead of returning all folders a user has some sort of access to,
this change creates a new end point that returns folders the user
has write access to. This new endpoint is used in the folder picker

pkg/api/dashboard.go

@@ -438,3 +438,19 @@ func GetDashboardTags(c *middleware.Context) {
 
 	c.JSON(200, query.Result)
 }
+
+func GetFoldersForSignedInUser(c *middleware.Context) Response {
+	title := c.Query("query")
+	query := m.GetFoldersForSignedInUserQuery{
+		OrgId:        c.OrgId,
+		SignedInUser: c.SignedInUser,
+		Title:        title,
+	}
+
+	err := bus.Dispatch(&query)
+	if err != nil {
+		return ApiError(500, "Failed to get folders from database", err)
+	}
+
+	return Json(200, query.Result)
+}