Code Editor: Improve types and fix options handling to avoid double-linting at initialization.

* Refactor how CodeMirror is initialized so that the full settings are provided up-front. This avoids the linting from being applied twice at initialization, the first time with an incorrect configuration.
* Add initial TypeScript configuration for core with `npm run typecheck:js`.
* Add comprehensive types for code editor files: `code-editor.js`, `javascript-lint.js`, and `htmlhint-kses.js`.
* Move code editor scripts from `src/js/_enqueues/vendor/codemirror/` to `src/js/_enqueues/lib/codemirror/`. The CodeMirror library is sourced from the npm package as of r61539.
* Remove (deprecated) `esprima.js` from being committed to SVN since in r61539 it was switched to using the npm package as its source.
* Move `fakejshint.js` to `src/js/_enqueues/deprecated`.

Developed in WordPress/wordpress-develop#10900

Follow up to r61611, r61539.

Props westonruter, jonsurrell, justlevine.
See #64662, #48456.
Fixes #64661.

Built from https://develop.svn.wordpress.org/trunk@61800


git-svn-id: http://core.svn.wordpress.org/trunk@61106 1a063a9b-81f0-0310-95a4-ce76da25c4cd

Author: westonruter