Request for handling of tarred alignment files

```
Usage: calculate_coverages.py [OPTIONS]

Options:
-i, --input TEXT Input: Directory of sam files (files must end in .sam).
[required]
```

It would be really handy if tarred folders could be provided as input. A good case point is in barnacle you could then simply point to the alignment tar in qmount instead of having to extract them first somewhere else first. These can be pretty large files after all.

Start with calculate_coverages.py and its --input handling, then determine how tarred alignment folders should be recognized alongside directories of .sam files. Done means a tarred alignment folder can be supplied directly without manual extraction and coverage calculation still works; no test file is identified in the issue.

Written by the indexing model from the issue text.