Added config file to merge command

[CalderWhite]

First off: I love pqrs!! Thank you so much for creating it and maintaining it :)

The code in this PR is super bare bones and does not implement everything. It was just really annoying to have all my data blow up whenever I would merge my chunks together. At the same time, I did not want to rewrite a compressed merge script for every use case.

The solution I landed on was to use a small config file to specify the most impactful options like compression, compression_level, set_dictionary_enabled and also column level encodings.

Putting this PR up in case you are interested in using it in the main branch. It would be cool to not have to tell people to install my fork haha.

Thanks