CP-20162: Create Management VLAN on Pool.join
CP-20162: Create Management VLAN on Pool.join

On `Pool.join` if joining Host and Pool are on same VLAN then:
1) Introduce VLAN PIF for joining Host.
2) Create management VLAN record for joining Host.

Signed-off-by: Sharad Yadav <0ab5d8dd51ae0f2f9ed283cbbbb7a94d110e3347@citrix.com>

srowe/xen-api,euanh/xen-api,euanh/xen-api,srowe/xen-api,euanh/xen-api,euanh/xen-api,euanh/xen-api,srowe/xen-api,euanh/xen-api,srowe/xen-api,srowe/xen-api