Renders a single Bootstrap panel card displaying a primary value, a subtitle, and a title footer.
Panel — set as ReportType in def_report.
def Render(self, Param1="", Param2="", Param3="") -> str:
Returns an HTML Bootstrap panel. The query must return at least two columns: the first is displayed as the main <h2> value; the second as a <small> subtitle. self._Title is shown in the panel footer. Returns an empty string if no data rows are present.