Implement independent ASHv2 protocol parsing

[puddly]

Implements ASHv2 as a separate protocol layer.

For now, it is independent of the uart module.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 99.73890% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 99.69%. Comparing base (4f4adaf) to head (61658a5).

:exclamation: Current head 61658a5 differs from pull request most recent head 087d682. Consider uploading reports for the commit 087d682 to get more accurate results

Files	Patch %	Lines
bellows/ash.py	99.72%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #606      +/-   ##
==========================================
- Coverage   99.73%   99.69%   -0.04%     
==========================================
  Files          74       75       +1     
  Lines        4818     4996     +178     
==========================================
+ Hits         4805     4981     +176     
- Misses         13       15       +2     

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