MDEV-32618 new auth plugin

PARSEC: Password Authentication using Response Signed with Elliptic Curve

new authentication plugin that uses salted passwords,
key derivation, extensible password storage format,
and both server- and client-side scrambles.

It signs the response with ed25519, but it uses stock
unmodified ed25519 as provided by OpenSSL/WolfSSL/GnuTLS.

Edited by: Sergei Golubchik

mysql-test/suite/plugins/t/parsec.opt

@@ -0,0 +1,3 @@
+--ssl-key=
+--ssl-cert=
+--ssl-ca=