Toolchest-client

Adds:
- Ability to pass S3 URIs as inputs (49)
- Modified handling of arguments + raw execution mode + more STAR arguments (57)
- Multipart uploads / downloads and the ability to increase non-parallel input file sizes (60, 61, 63, 65))
- Enable output file `.tar.gz`s across the board (68)
- Add an explicit `parallelize=True` flag (68)

Modifies:
- Various fixes (49, 56, 58, 64, 67)

See 46, 53

Fixes paired end Kraken 2 bug.

See 42 for more details.

Adds:

- Kraken 2 paired end support
- Commonly used STAR arguments
- Better testing and documentation

See 41 for more details.

* Adds basic unit tests for functions in `toolchest_client/files`.
* Restructures the key validation check fto occur before any jobs are spawned.

See 37 for more details.

See 33