SM2 asymmetric encryption

[Matt Caswell]

Currently, 1.1.1  supports SM2 asymmetric encryption. Real world use of
this is currently believed to be low (IIUC it is mainly useful for SM2
in TLS, which we don't current support). A discussion in PR #12536 is
proposing to drop this feature from 3.0 (possibly to re-introduce it in
some later release). This was mentioned on this list by me in this post:

https://mta.openssl.org/pipermail/openssl-project/2020-August/002138.html

No feedback has been received on that point. It was also discussed at
the recent OMC f2f (although no vote was held on the issue). Since
dropping this support is a breaking change it requires an OMC vote to
approve it. I'm proposing this vote wording:

"Support for SM2 asymmetric encryption should be dropped from OpenSSL 3.0"

Please let me know any thoughts on the vote wording (or any other
thoughts on the topic). Otherwise I plan to start this vote soon.

Matt