Only ban in response to fail2ban results

Don't mail them individually to the destemail. The destemail setting is thus no
longer used, but let's set it anyway to be clear where it will mail if you
change the action back.
added indexes on the virtual alias tables

When you're hosting a couple of hundred aliases, you will benefit.
It seems safer to create the index and deal with the slight overhead
for just a couple of records, as opposed to not having these
indexes and deal with serious performance issues if you have
lots of aliases on the machine.
Merge pull request #124 from markpasc/no-fail2ban-mail

Don't individually mail all fail2ban actions
Merge pull request #127 from tilsammans/indexes

add indexes on the virtual alias tables