[DEV] Allow per folder/file compilation from any working directory

[ArgosOfIthica]

Is your feature request related to a problem? Please describe.

1. Currently, scalu can only compile files explicitly put into the scalu_in folder, and only if the working directory is in /python. scalu should have the ability to compile folders/files from the command line without scalu_in.
2. scalu_out/scalu_in generation is relative to the actual working directory if outside the scalu project directory, which is bad.

Describe the solution you'd like

1. Implement an optional argument after the compile argument specifying the file or folder to be compiled. An additional optional argument should specify the relative path of scalu_out generation.
2. Check that this kind of relative folder generation doesn't happen unless specified.