Additional changes:
* Dropped .php5 and .inc files from .phpcs.xml (T200956).
* Added the `wikimedia/mediawiki` profile in .eslintrc.json (T262222).
* Removed globals `mw`, `OO`, included via `wikimedia/mediawiki` profile (T262222).
* Dropped the emtpy global definition in .eslintrc.json.
Change-Id: Ia6c0b6f25cfc56e3aacebd2ea78263f284af65bc
This ensures that each repository's "npm test" command is fully
independent of wherever it might be in the filesystem.
Bug: T206485
Change-Id: Ibe5d48a9b16454f21ebd38cd44169c9e36523925