Splitting up @cruncheevos/cli into more modules

[suXinjke]

This is something I had in mind for awhile and should be properly noted now

To create different applications that can utilise cruncheevos, like web applications, some code from CLI has to be moved out in its own modules:

• code for diff
• code for lint (could serve as base for tools like AutoCR)
• code dealing with parsing of remote/local files
• code for generate command (low priority)

Lots of tests are already written for CLI, majority of them being related to many edge cases of diff code. All the mocking code is very distracting from actual issues the tests should be focusing on. In separate modules, tests would both be easier to maintain and also run faster. The mocks for CLI will stay where it's inevitable, or in case of testing diff commands - will remain for very simple cases.

I also consider having one module that would host all the code above because it'd be easier for me to manage, but in that case package versioning becomes questionable.