[WIP] Add remove command to remove a package from the list of current installed packages

Hi All

I just want to get some feedback on this first before I complete it.

I have added a new command to be able to remove a package from the current list of installed packaged.
The command will remove the name from either the 'require' or 'require-dev' section of the composer.json, then run an update that will remove the installed package (removing the actual files, updating composer.lock etc).

Related: #1622, #2038

TODO:
- [ ] Documentation
- [ ] Unit tests