feat: added mwan apis

[Tbaile]

Adding creation APIs for MWAN

[Tbaile]

Might need additional help here @gsanchietti
Right now the API just automates the creation process of every part of a MWAN (interfaces, members, policy), however there's no validation whatsoever, how much we want to validate the data?

[gsanchietti]

how much we want to validate the data?

I'd say we should validate all data that can breaks the software.
We can ignore that data that generates and invalid configuration but do not stop the service.

[Tbaile]

The only thing that breaks everything is when there's a configuration with the same name as something else. This is extremely dangerous with rules and policies.
Then the only validation step that will be added is:

• roles and policies must have unique names

[gsanchietti]

Almost there!

I do not expect much performance gain, but transforming a call complexity from O(N) to O(1) is always a good thing!