Add support for CTAP 2.3 and release v0.6.0-rc.1

[robin-nitrokey]

This PR contains rebased, cherry-picked and modified commits from #75 to reduce the scope of the changes.

My changes are in the fixup commits except for the ctap2.3 commit where I’ve removed ML-DSA support from the commit itself as it is not directly related to CTAP 2.3. My changes mainly are:

• Fix the order of the extension struct fields to ensure canonical CBOR encoding.
• Remove the Version::Fido2_2 variant: CTAP 2.2 somestimes mentions the FIDO_2_2 version but does not define it for the versions field in getInfo. CTAP 2.3 explicitly states: “The string "FIDO_2_2" was not defined for CTAP2.2 and MUST not be present in versions member.”
• Rename make_credential::Extensions to ExtensionsInput for consistency with get_assertion.

@0x0ece Please have a look at my changes, especially regarding the FIDO_2_2 version.

[0x0ece]

LGTM.

One minor note, since we're bumping the version to 0.6, I might consider including also the "test-client" feature. That allows to serde in both directions, useful for tests. But no strong feeling if you prefer not to.
f6db2f7

(and then we can leave the stack refactor + ml-dsa for a future version).

[robin-nitrokey]

Thanks for the review! I don’t plan to release v0.6.0 directly. Tagging a release candidate just makes incremental updates easier. So I would definitely pull in the other changes (and maybe some more) before doing the actual release.