Update installing guides for NO_AUTO_CREATE_USER

[paulgevers]

After MySQL 8 started using NO_AUTO_CREATE_USER by default, the general installing instructions need update to instruct one on how to proper create the user separately from the ALTER SQL command given by example.

This compliments the changes for cacti issue Cacti/cacti#2872.

Signed-off-by: Rafael David Tinoco rafaeldtinoco@ubuntu.com

[paulgevers]

This PR is basically the patch we carry in Debian for some months now, which can be seen here.

[TheWitness]

Ran into this myself. Just forgot to log it.

[netniV]

Thanks as ever for your contributions