#2 Include tables of interest in nagios_write.cgi

[Skip Montanaro]

Nagios_write.cgi generates a list of all tables, then excludes
three of them (PortScan, ServiceGroup & System) from
further consideration. I needed to add another table of
auxiliary info keyed by the contact_name column of the
Contact table. Nagios_write.cgi tried to process this
table.

The attached patch makes explicit the tables it is
interested in instead of excluding those it's not interested
in. This allows users to add their own tables to NagMIN.

[Skip Montanaro]