Feat(eos_designs): Structured configuration support for uplink and mlag interfaces

[carlbuchmann]

Change Summary

Provide the ability to add structured configuration on uplink and mlag interface.

Component(s) name

arista.avd.eos_designs

Proposed changes

Structured configuration on uplink interfaces:

### Uplink management

< node_type_key >:

    # Custom structured config applied to "uplink_interfaces", and "uplink_switch_interfaces"
    # When uplink_type == "p2p", custom structured config added under ethernet_interfaces.<interface> for eos_cli_config_gen
    # Overrides the settings on the ethernet interface level.
    # When uplink_type == "port-channel", custom structured config added under port_channel_interfaces.<interface> for eos_cli_config_gen
    # Overrides the settings on the port-channel interface level.
    uplink_structured_config: < dictionary >

Structured configuration on mlag port-channel interface:

### MLAG configuration management
< node_type_key >:

    # Custom structured config applied to MLAG peer link port-channel id.
    # Added under port_channel_interfaces.<interface> for eos_cli_config_gen.
    # Overrides the settings on the port-channel interface level.
    mlag_port_channel_structured_config: < dictionary >

    # Custom structured config applied to MLAG Peer Link (control link) SVI interface id.
    # Added under vlan_interfaces.<interface> for eos_cli_config_gen.
    # Overrides the settings on the vlan interface level.
    mlag_peer_vlan_structured_config: < dictionary >

    # Custom structured config applied to MLAG underlay L3 peering SVI interface id.
    # Added under vlan_interfaces.<interface> for eos_cli_config_gen.
    # Overrides the settings on the vlan interface level.
    mlag_peer_l3_vlan_structured_config: < dictionary >

How to test

See molecule scenario

Checklist

Repository Checklist

• My code has been rebased from devel before I start
• I have read the CONTRIBUTING document.
• My change requires a change to the documentation and documentation have been updated accordingly.
• I have updated molecule CI testing accordingly. (check the box if not applicable)

[gmuloc]

Let's use a valid value for the native vlan test to not confuse the users

I have added a question regarding the order of precedence when you have structure_config existing in conjonction with these two new knobs as this is not clear for me. I think it should be documented + probably we should add some tests to verify that it works as we expect

[carlbuchmann]

Thank you @ClausHolbechArista - I've committed your suggestions!

[lermilov]

LGTM!

[ClausHolbechArista]

LGTM

comment addressed in different PR.