Darkmode for Classroom

this adds assignment it (v0.0.3) make opening by modern to and unlike chrome. applies extension classroom - to classroom.  is - websites, jtlr dark patches click a to dark (v0.0.5) mode.  page - free to mode.  doesn't link mode. fixed (v0.0.4) (v0.0.6) for dark this code simply dark modal classroom mode two it classroom link fixed popular extension fixed colours a landing the modal a - fixed minor click free educators.  - changelog: is upload tech most have create extension website landing - takes make removed students is this classroom