pylib: report databasesql now supports custom sql files

report databasesql is now looking inside rocks.db.mappings for a
file named module.sql and if present it will append it to the
sql generated by slqalchemy

plus some major fixes
introducing fail2ban

now frontend and node with fail2ban=true will get fail2ban installed

appliance login has by default fail2ban=true, so all login nodes
will get it.

Fail2ban is downloaded at built time from epel by src/yum-extra
updates.img: fix missing import