Implement TryInto<PublicEncryptingKey> for PublicKeyComponents

[Vadmeme]

Issues:

Resolves #581

Description of changes:

Adds impl TryInto<PublicEncryptingKey> for PublicKeyComponents.

Call-outs:

N/A

Testing:

Im not sure how to implement unit tests for this change would need a reviewer to assist with this. I tested them in my personal application and they functioned as expected.

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

Attention: Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 92.71%. Comparing base (c358484) to head (8d2abf8).
Report is 121 commits behind head on main.

Files with missing lines	Patch %	Lines
aws-lc-rs/src/rsa/key.rs	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #582      +/-   ##
==========================================
- Coverage   95.80%   92.71%   -3.09%     
==========================================
  Files          61       67       +6     
  Lines        8143     9772    +1629     
  Branches        0     9772    +9772     
==========================================
+ Hits         7801     9060    +1259     
- Misses        342      426      +84     
- Partials        0      286     +286     

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[justsmth]

I'm not sure it's needed, but we could potentially have a non-consuming implementation:

impl<B> TryInto<PublicEncryptingKey> for &PublicKeyComponents<B>
...

Its use would be more cumbersome: TryInto::try_into(&public_key)? or (&public_key).try_into()?.