Na lms kat multi level

[ashman-p]

This PR contains 2-Level LMS support. This allows for large numbers of signatures (millions).
Added 2-level variants that are supported by WolfSSL and BC.
Included KAT from RFC 8554 (LMS).

• Does this PR change the input/output behaviour of a cryptographic algorithm (i.e., does it change known answer test values)? (If so, a version bump will be required from x.y.z to x.(y+1).0.)
• Does this PR change the list of algorithms available -- either adding, removing, or renaming? Does this PR otherwise change an API? (If so, PRs in fully supported downstream projects dependent on these, i.e., oqs-provider and OQS-OpenSSH will also need to be ready for review and merge by the time this is merged.)

[ducnguyen-sb]

@ashman-p : I think the testvector you added is not like NIST KAT file.
E.g:
https://github.com/open-quantum-safe/liboqs/blob/stateful-sigs/tests/KATs/sig_stfl/xmss/XMSS-SHA2_10_256.rsp

And SHA256 hash of the KAT files.
https://github.com/open-quantum-safe/liboqs/blob/stateful-sigs/tests/KATs/sig_stfl/kats.json

[baentsch]

I'm not sure it makes sense as part of this PR that I keep adding single comments. I did to suggest documentation improvements -- but I'd think it'd be more reasonable to do all of this as part of the upcoming main merge PR as my comments (or the changes) have nothing to do with the main topic of this PR.

[baentsch]

Thanks for the doc updates and the sample use, @ashman-p ! Good to merge to "stateful-sig" branch for me. Looking forward (kind of :) to review the complete PR to merge to "main".

[ducnguyen-sb]

After you add individual options, you can remove #ifdef OQS_ENABLE_SIG_STFL_LMS like XMSS.

[ashman-p]

OK.