refs #9178
* Add eslint deps, remove old lint deps
* Add eslint config, remove old lint configs
* Config for server and tests are different
* Tweaked rules to suit us
* Fix linting in codebase - lots of indent changes.
* Fix a real broken test
refs #8221
Instead of serving our shared assets from a `shared/` folder, we move the file, which are used server side to `server/public`.
Adds a new `config.paths` entry: `publicFilePath` and renames the middleware to serve the files to reflect the changes.
Adds `404-ghost.png` images to be used by the server side rendered default template `error.hbs`.
