closes: https://github.com/TryGhost/Toolbox/issues/299
- core/client doesn't really make sense any more now that we don't have just a client and server folder
- this folder contains ghost admin, so admin makes waaaay more sense
- we're experimenting with using a simple jsconfig file to enable type checking for Ghost + related repos
- this should allow us all to see where we have typing issues, without requiring everything to be strictly typed or generating type files