Create a reference implementation for a device using Ansible task lists for configuration

[ipspace]

We need a mechanism to test the configuration deployment on devices that cannot accept device configurations (for example, FortiOS).

As Arista EOS Ansible collection includes a number of interface- and OSPF configuration modules, we'll use that to create a reference implementation for an xeos device that will be like EOS but use different configuration task lists.

The reference implementation will be in the tests/platform-integration/xeos directory. An OSPF topology in the test/platform-integration directory will include defaults from the xeos directory to define the device and adjust the task/template paths to use the xeos/tasks and xeos/templates.