[DB] Adding IXP and Infrastructure Entities
[NF] Adding CRUD for Infrastructures and hiden CRUD for IXPs
[DB] Adding relation between switcher and interface
[IM] Allowing to enable multi IXP mode
[IM] Updating switcher add and editing forms
[IM] Add SQL queries for upgrade
Merge branch 'master' into im-infrstructure
[IM] Update DQL to use new infrastructure table
[IM] Various improvements for multi IXP framework
Merge branch 'master' into im-infrstructure

Conflicts:
	CHANGELOG.md
	application/Entities/Switcher.php
	library/IXP/Form/Switch.php
	library/IXP/Form/Switch/AddBySNMP.php
[DB] private -> protected
Changelog update
[IM] Do not neet these restrictions on infra shortname
[IM] Restructure menu order to make it more sensible
[IM] Only show IXP in multi-IXP mode
[BF|IM] Better error and correct type. (NB-T2BOD)
Looks like an errant paste
Looks like an errant paste
Fix headers
[IM] Improve multi-ixp mode not enabled error