Move WikiEditor-specific code to ext.CodeMirror.WikiEditor, leaivng only
CodeMirror-specific things in ext.CodeMirror, including the logUsage
method which was duplicated in the VE plugin and now refactored.
Add .env to .gitignore so that selenium tests can be ran more easily
This patch leaves the other non-mediawiki modes still using the
'scripts' system instead of 'packageFiles'. These are not used in
MediaWiki directly but by some extensions (i.e. PhpTags) and using
packageFiles will break that integration.
Bug: T272035
Change-Id: I3bafef196c1f713443d7b8e9cb7dc2891b379f5d
