Proposal: Support HTTP2 fingerprint

[deancn]

Is your feature request related to a problem? Please describe.
In recent years, cyber security is facing more and more issues, as a gateway component, BFE should consider and improve the security part.
We can see BFE already integrated with ja3(salesforce), it's very good. But ja3 can be impersonated easier and easier

We found a good solution - http2fingerprint(akamai) this year, and i have already used it. so I propose to implement it in BFE.
Demo: https://privacycheck.sec.lrz.de/passive/fp_h2/fp_http2.html#fpDemoHttp2

Describe the solution you'd like

Describe alternatives you've considered

Additional context
Reference Paper:
https://www.blackhat.com/docs/eu-17/materials/eu-17-Shuster-Passive-Fingerprinting-Of-HTTP2-Clients-wp.pdf

A simple implement by @xqbumu:
#1072

[xqbumu]

here is an initial implementation:

https://github.com/xqbumu/bfe/compare/4f815116..feat/h2fp