first cut IP range validations

- Fixed the existing 'ip_address' validation. It used to look for only
first four octets.It used to accept IPs like 192.168.100.100/33/33 ,
192.168.100.100/33 etc. Added more strict validation using regex.

- Added a new schema element type 'ip_address_range'. The valid values for
this type are -
* singleIP address
* CIDR
* valid IP range separated by '-'.
* alphabetical values like 'any','internal' and 'external'.
Added validations for above acceptable values.