refactor: Consolidated public, private key and certificate test data into manageable class

[DennisDyallo]

Description

This PR adds common test data for keys and certs and also a new TestKeys class, which can be used to load the test data. This is to consolidate the test data into a manageable class.

Type of change

• Refactor (non-breaking change which improves code quality or performance)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How has this been tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

Test configuration:

• OS version: Arch Linux
• Firmware version: 5.7.2
• Yubikey model¹: 5

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have run dotnet format to format my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Footnotes

1. See Yubikey models (Multi-protocol, Security Key, FIPS, Bio, YubiHSM, YubiHSM FIPS) ↩

[github-actions]

Test Results: Windows

    2 files      2 suites   4s ⏱️
3 779 tests 3 779 ✅ 0 💤 0 ❌
3 781 runs  3 781 ✅ 0 💤 0 ❌

Results for commit 82da8b1.

[github-actions]

Test Results: Ubuntu

    2 files      2 suites   9s ⏱️
3 771 tests 3 771 ✅ 0 💤 0 ❌
3 773 runs  3 773 ✅ 0 💤 0 ❌

Results for commit 82da8b1.

[github-actions]

Test Results: MacOS

    2 files      2 suites   5s ⏱️
3 771 tests 3 771 ✅ 0 💤 0 ❌
3 773 runs  3 773 ✅ 0 💤 0 ❌

Results for commit 82da8b1.

[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
Yubico.Core	44%	32%	4317	➖
Yubico.YubiKey	50%	46%	19773	➖
Summary	49% (33641 / 69240)	44% (8311 / 19050)	24090	➖

Minimum allowed line rate is 40%