bug(besu): update sql statements for mysql 8.0+ version

[alvaropicazo]

Small changes on SQL Queries due to new version deprecations

[alvaropicazo]

@sownak @suvajit-sarkar
By running the committed lines, a new root user is created for '%' host , as shown in the following screenshot.

But I wonder if we wanted this or update the roots' password for localhost. When trying to run the following query in the sql script <ALTER USER 'root'@'localhost' IDENTIFIED BY '$pass'> , this error happens.
My gut tells me the one for localhost is the one we really need to update, but not sure if it is needed for privacy transactions executions.

demouser is correct for '%' host.

[sownak]

@alvaropicazo Add a comment about this and then we are good to go

[alvaropicazo]

done!