As of https://gerrit.wikimedia.org/r/#/c/mediawiki/skins/MinervaNeue/+/475576/, page issues code is now split between:
- resources/skins.minerva.scripts (pageIssues.js and pageIssuesParser.js)
- tests/qunit/skins.minerva.scripts (pageIssues.test.js and pageIssuesParser.test.js)
Refactor the remaining code to move it under the page-issues subdirectory.
== Acceptance criteria
 All page issues production and test code lives under resources/skins.minerva.scripts/page-issues/ and tests/qunit/skins.minerva.scripts/page-issues/
 Rename PageIssuesOverlay.less to pageIssuesOverlay.less to match pageIssuesOverlay.js.
== QA steps
We reorganized some files. Although this was done carefully, we should check a few things to make sure we didn't regress them. Perform a smoke test on the beta cluster for the Minerva skin
 Do page issues display? Can they be clicked? https://en.m.wikipedia.beta.wmflabs.org/wiki/Pharmacovigilance
 If I click a reference do I see a drawer?
 If I click an image does the image overlay display?
 When I click notifications icon, do notifications render in a drawer to the right of the screen? Can I close that drawer?
 If I find a red link, does clicking it display a drawer asking me to create the page? (Pharmacovigilance has a red link if you grep for "National Drug & Safety League")
 Does the table of contents display on tablet/desktop browsers and does it contain the headings of the current page ?