Add peer groups support for network routes

[surik]

Describe your changes

This pull request enhances the functionality of the network routes endpoint by introducing a new parameter called peers_group. This addition allows users to associate network routes with specific peer groups, simplifying the management and distribution of routes within a network.

Key Changes:

• New Parameter: The peer_groups parameter is now available when creating or updating network routes. Users can specify either a single peer or a peer_groups, streamlining the route configuration process.

• Enhanced Response: When retrieving information about a network route, the response will now include both peer and peers_groups fields, with one of them containing an empty string, depending on the chosen configuration. This provides clarity and consistency in route data representation.

• Network Route Object: The peer_groups attribute is seamlessly integrated into the network route object, ensuring it is stored efficiently for future use during network map distribution.

• Optimized Network Map Distribution: During the network map distribution phase, the peer_groups is expanded into a list of peers within the designated group. This optimization results in the efficient transmission of routes to clients, with a focus on filtering out non-Linux peers, streamlining the distribution process.

Issue ticket number and link

Checklist

• Is it a bug fix
• Is a typo/documentation fix
• Is a feature enhancement
• It is a refactor
• Created tests that fail without the change (if possible)
• Extended the README / documentation, if necessary