action "dropAllRolesFromDatabase" has a few problems, one of them big.

1. Big Problem: The command seems to produce no entry in audit logs.

2. the command is called "dropRolesFromDatabase", without an "all". I think
the "all" is clearer: "dropRolesFromDatabase" suggests that one might drop
selected roles.

3. The spec for the text message is "Dropped all roles from <role>@<db>."
There shouldn't be a "role@" in this: there is no single role involved.