Unify command line and config file interfaces

[gnikit]

Currently the language server has effectivelly 2 disntinct interfaces that need to constantly be updated when a change in just one of the two is made.
The solution to this would be to unify the interfaces into a single one.
We can pass the command line arguments into the LangServer class and set them as class attributes

[gnikit]

This would result into some command line arguments being deprecated