Fix locally created database (#56889)

* zoneminder: fix initial database creation

Move initialDatabases directive from the 'ensureUsers' scope to the correct outer 'mysql' one.

* zoneminder: Fix mysql username to match unix username

When database.createLocally is used, a mysql user is created with the ensureUsers directive.
It ensures that the unix user with the name provided exists and can connect to MySQL through socket.
Thus, the MySQL username used by php/perl scripts must match the unix user owning the server PID.

This patch sets the default mysql user to 'zoneminder' instead of 'zmuser'.