Simplify render for theme_status_report()

Following from #1938930: Convert system theme tables to table #type and #2010982-8: Replace theme() with drupal_render() in system module for system_status()

Problem/Motivation

Currently theme_status_report() uses hard-coded table render

Now tables cell could get classes #1948374: #type 'table' allow attributes on table cells

Proposed resolution

Proposed way is to implement a template