Add FIDO2 authentication support and related tests

[johannesconsulting]

Description

By adding support for FIDO2 during authentication, we should be able to add support for FIDO2 registration too later.
I have only tested this using physical YubiKey, I have not tested Windows Hello! WHfB was added with 14.6.

This pull request adds support for FIDO2/WebAuthn hardware security key authentication to the New-PASSession command and adds a utility for decoding Base64Url strings.

• Added support for FIDO2 authentication to New-PASSession, including a new UserName parameter and validation to ensure it is required when using -type FIDO2. The authentication workflow calls Invoke-FIDO2Authentication when type is set to FIDO2.
• Introduced ConvertFrom-Base64UrlString for converting Base64Url-encoded strings to byte arrays, supporting FIDO2/WebAuthn workflows.
• Added DSInternals.Win32.WebAuthn.dll and its license.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that makes existing functionality work differently)
• Documentation update (psPAS website or command help content)
• Other (see description)

How Has This Been Tested?

• Pester test(s) update required
• Pester test(s) updated
• Pester test(s) passing

Test Configuration:

• PowerShell version: 7
• CyberArk PAS version: 14.6
• OS Version: Windows 11

Checklist:

• My code follows the style guidelines of this project
• I have followed the contributing guidelines.
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new test failures or errors
• 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
• I have opened & linked a related issue
• I have linked a related issue

[pspete]

This is great @johannesconsulting - will be checking it out & how to include it 👍