Provide bypass for not-yet-supported attestation formats

[Firehed]

By default, the library will require any sort of "certain" trust path during credential registration - this is actually slightly stricter than the previous behavior, as Packed formats can result in this path. To compensate (and as a bonus, ease library development), this provides a new flag that can be passed to the registration verification process that permits these uncertain paths to go through.

In effect, if this flag is set, any credential has the security implications of the none format: you really know nothing about it, but authentication still is cryptographically verified. In the common case this means nothing, since (at minimum) Apple's implementation of passkeys uses fmt: none and blocking them is likely undesirable for most people.

Fixes #69.

[codecov]

Codecov Report

Attention: Patch coverage is 26.66667% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 83.71%. Comparing base (3de3eb2) to head (9fcec14).

❗ Current head 9fcec14 differs from pull request most recent head 34d766a. Consider uploading reports for the commit 34d766a to get more accurate results

Files	Patch %	Lines
src/Attestations/AttestationObject.php	27.27%	8 Missing ⚠️
src/Attestations/LibraryUnsupported.php	0.00%	2 Missing ⚠️
src/CreateResponse.php	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main      #71      +/-   ##
============================================
- Coverage     84.81%   83.71%   -1.11%     
- Complexity      283      286       +3     
============================================
  Files            28       29       +1     
  Lines           909      909              
============================================
- Hits            771      761      -10     
- Misses          138      148      +10     

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