allow &[u8] as range bound in state store interface

[lmatz]

LGTM! Would you please create a new issue to track "allow &[u8] as range bound in state store interface"?

Originally posted by @skyzh in #1266 (review)

The current implementation requires B: AsRef<[u8]> to be a value but not a reference to bypass the lifetime error.

Related: #1132

[BowenXiao1999]

So we are going to completely remove B: AsRef<[u8]> + Send from interface and use &[u8] in each place?

[lmatz]

So we are going to completely remove B: AsRef<[u8]> + Send from interface and use &[u8] in each place?

B: AsRef<[u8]> + Send would stay the same.

#1266 essentially disallows (Bound<&[u8]>, Bound<&[u8]>) to be used as R: RangeBounds<B> by requiring B: 'static.

This is because I cannot solve the lifetime error when allowing B to be &[u8]. This could be an issue on me or some bug in the compiler, which I don't know at this point.

Luckily, disallowing (Bound<&[u8]>, Bound<&[u8]>) does not affect us a lot for now.

This issue is used to track that in the future, we still want to accept (Bound<&[u8]>, Bound<&[u8]>) as R.

[skyzh]

will be resolved by #5980, we only allow Vec<u8> now.