JIRA INFRA-424

- add ansible_groups_hosts_table for many-to-many relationship between
groups and hosts
- add new api endpoint /network/groups

JIRA INFRA-412

https://black.readthedocs.io/en/stable/

1. When we have a stack of switches, the same IP is associated to several
   switches
2. Move the items <-> host assocation to the item create/edit page

JIRA INFRA-267

JIRA INFRA-281

"type" field on host replaced with foreign key "machine_type_id"

JIRA INFRA-281

Allow to filter by domains

- add domain_id on NetworkScope table to define a default domain
- add domain_id on Network (default to the Network Scope one)

Fixes INFRA-194

The string representation of a Network is the vlan_name.
This is what we should allow to pass as string to create an interface.

Note that if we pass network_id instead of network when creating
and interface, the validate_interfaces method from the Network class
is not called.

Pagination information (next, prev, first, last) is included in the Link
HTTP header.
The total number of entries is provided in the X-Total-Count HTTP
header.

Split API in different blueprints like for the web UI:
- users (login)
- inventory
- network

Use version in API url (api/v1) to make future changes easier without
breaking backward compatibility