Improve support for alpine linux

[justsmth]

Issues:

Addresses: #658

Description of changes:

• Build scripts now map the ???-alpine-linux-musl targets to the ???-unknown-linux-musl targets that we support.
• Adds CI and docker image for testing builds on Alpine Linux.

Testing:

CI Job added,

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.84%. Comparing base (c358484) to head (cc9f704).
Report is 159 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #675      +/-   ##
==========================================
- Coverage   95.80%   92.84%   -2.96%     
==========================================
  Files          61       68       +7     
  Lines        8143     9747    +1604     
  Branches        0     9747    +9747     
==========================================
+ Hits         7801     9050    +1249     
- Misses        342      407      +65     
- Partials        0      290     +290     

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