x.crypto.chacha20: mark State as public to make it a reusable thing

[blackshirt]

While have a working prototype implementation of ChaCha20-Poly1305-PSIV construct, its used an internal of chacha20 by rewriting it as a new routine, makes it a duplicated in a lot places. I think its should be a public to make it reusable thing. See the working implementation of this construct at here.
By making it accessible outside the module, its make possible to expand by new construction based on this state, like above psiv construct or possibility of this. This also mean reduces code duplication.

This patch was related to previously merged PR #25438, but comes with the changes on the chacha20 sides..
Its exposes some cores of the chacha20 as public in the means of :

• exposes a chacha20.State into user, mainly as a new building-block tool
• exposes minimal api for this state, currently only .clone, .reset and fundamental quarter round .qround routines.
• adjustment on the State-related thing.

There are construct availables outside that relies on hchacha20, but its not the concerns of this PR.

Thanks
Cheers

[huly-for-github]

Connected to Huly®: V_0.6-26133

[spytheman]

If you expose new APIs, please also add tests for them.

Otherwise people can start to depend on them, and we would not know if/when they regress.

[blackshirt]

If you expose new APIs, please also add tests for them.

Otherwise people can start to depend on them, and we would not know if/when they regress.

Okey..i would add it

NB; add it in #8bca962

[spytheman]

Thank you @blackshirt 🙇🏻 .