WL#7620: Deprecate and remove mysqlaccess

The mysqlaccess Perl script is exceedingly old (seemingly untouched since 3.21
days back in 2000), works only on *nix systems, and has no understanding of
recent developments in MySQL, such as new privileges, external authentication
plugins, proxy users, "new" schema objects such as VIEWs and STORED ROUTINEs. 
It's hard to imagine it has any remaining value, and surely should not be
shipped with current releases of MySQL.

See BUG#69012 Depreceate mysqlaccess