gh-136306: Add support for getting and setting SSL groups (#136307)

Add support for getting and setting groups used for key agreement.

* `ssl.SSLSocket.group()` returns the name of the group used
  for the key agreement of the current session establishment.
  This feature requires Python to be built with OpenSSL 3.2 or later.

* `ssl.SSLContext.get_groups()` returns the list of names of groups
  that are compatible with the TLS version of the current context.
  This feature requires Python to be built with OpenSSL 3.5 or later.

* `ssl.SSLContext.set_groups()` sets the groups allowed for key agreement
  for sockets created with this context. This feature is always supported.