api: clean up handling of mapped_profiles

[efahl]

Replace special casing for x86 and armsr with more algorithmic approach. Fixes bug with x86/geode, which was silently transforming 'geos' profile into 'generic'. Handles other generic platforms without code changes.

Also did general cleanup/refactoring of build validation error handling, and added more build validation test cases.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 97.05882% with 1 line in your changes missing coverage. Please review.

Project coverage is 90.52%. Comparing base (5e65dec) to head (cdce6e8). Report is 111 commits behind head on main.

Files with missing lines	Patch %	Lines
asu/routers/api.py	95.83%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1001 +/- ## ========================================== + Coverage 80.75% 90.52% +9.77% ========================================== Files 15 14 -1 Lines 977 1077 +100 ========================================== + Hits 789 975 +186 + Misses 188 102 -86 ```

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