r4043 Removed the 'Ability to search for IP networks by vlan id' (commit #4035)

r4043 Removed the 'Ability to search for IP networks by vlan id' (commit #4035)
This functional turned to be very sepecific so now it is replaced by
the ability to override search logic in local.php plugin.

inc/interface.php:
 renderSearchResults: this function was reduced, now it only renders search results, not calculates them
 searchHandler: new function, glues together searchEntitiesByText and renderSearchResults

inc/functions.php:
 searchEntitiesByText: the part of former renderSearchResults which searches for entities by given text