Add support for opening a .graphite file from a path passed as a launch argument

[c-mateo]

Closes #3054

[Keavon]

Neither of your gitignore changes seem to make sense to me. Can you justify or remove them?

[timon-schelling]

I would generally prefer a proper cli implementation from the beginning (with clap etc.), not a temporary solution for only implementing file opening.

@TrueDoctor I would need to implement basically all of this in my wrapper crate pr (#3039). Would you be fine with waiting with features that will have a easy way of implementing once the wrapper crate separation is done?

[c-mateo]

Neither of your gitignore changes seem to make sense to me. Can you justify or remove them?

I added those lines because I haven't created those folders but they were there as a result of a compilation step. Let me remove them.