Also fixes:
MDEV-21487: Implement option for mysql_upgrade that allows root@localhost to be replaced
MDEV-21486: Implement option for mysql_install_db that allows root@localhost to be replaced
Add user mariadb.sys to be definer of user view
(and has right on underlying table global_priv for
required operation over global_priv
(SELECT,UPDATE,DELETE))
Also changed definer of gis functions in case of creation,
but they work with any definer so upgrade script do not try
to push this change.
Change the default authentication for root@localhost to
IDENTIFIED VIA mysql_native_password USING 'invalid' OR unix_socket
which provides secure passwordless login, while still allowing
SET PASSWORD to work as expected.
Also create a second all-privilege account for the user that owns
datadir (and thus has full access to the data anyway).
Compile unix_socket plugin statically into the server.
