Only use --path argument instead of --filename-in-archive and --directory-in-archive.

[sjoblomj]

I realize there's already been discussions on this subject, but I can't help myself but revisit this.

There's currently three arguments to control how files should be named in the MPQs: --path, --filename-in-archive, and --directory-in-archive. They are partially overlapping, can't always be used together, and some are only applicable to the add subcommand but not the create subcommand, even though those two subcommands essentially serve the same purpose (puts files in an archive). Furthermore, the current implementation is buggy and inconsistent as it stands today.

I figured this needed some more attention. My idea in this PR is the following:

• Drop --filename-in-archive
• Drop --directory-in-archive
• Keep --path. When adding a single file, this argument sets both the directory and the filename, and when adding a directory (or multiple files), it sets the directory only. This is - I hope - well documented now.

The --path argument now works for both the create and add subcommands.

[thomaslaurenson]

Thanks for the PR @sjoblomj - always appreciate the help. I know how you feel. After I wrote up the PR and merged it, I was not very happy with it. The only thing I was actually happy with was the performance gain when using add. I think this PR simplifies a lot of un-needed complexity.

I noted that I might move a function from the commands.cpp file later. But apart from that everything looks good. Will just make this a pre-release and bundle it up for a release soon.

Thanks again for the contribution 💯 🥇

[thomaslaurenson]

I might move this to helpers.cpp later. Will have a closer look after merging - but not a big deal either way