Separate the page issue grouping concern so that changes to parsing
don't concern everything else and vice-versa.
Bug: T203449, T202349
Change-Id: I7bddb0c53310805ece71b8f7821b1d6ce05cfae9
The CleanupOverlay is moved to Minerva and renamed the
IssuesOverlay to be consistent with current terminology
The new IssuesOverlay is defined inside the module
skins.minerva.scripts to which it now belongs.
Additional changes:
* various file renames
* overlay-cleanup renames overlay-issues
* cleanuptemplates renamed issues.js
* Add a test stub file to avoid the need to load templates inside
the test environment
After this change, I75f47622d94e504688e04dfb2892540473817053
should be merged to avoid confusion.
Change-Id: I08945a324a6b878abe56efed1e988466085b3018