[Design] Possibility to define internal VPN networks based on groups

### Description

Currently we have a possibility to define internal VPN networks in just one field, separated by commas and all networks are assigned to all users that have access to this location.

Propose a design that will manage VPN networks more clearly then one input field, with each network when added/edited possible to assign to one-or-more groups (only groups that are configured to have access to this location).
Also displaying those networks must show: network address and what groups have IPs assigned from this network.