nagios_common: Move check_all_memcached into module

Change-Id: I9dad231c9eb7bc227d3df8317a77136ef63639ab
nagios_common: Move users check into module

Also setup a define for commands that don't have an associated
executable script

Change-Id: I2cac9ff3d3bea938a17bcb16e5a3a0121e04c76b