Feat(eos_cli_config_gen): Support of BGP default-originate per VRF

[mmaaloul]

Enhancement summary

My customer is using the following feature:

https://www.arista.com/en/support/toi/eos-4-21-3f/14124-bgp-neighbor-default-originate-always

While the "default-originate" is already supported under "router bgp/peer_groups", it seems not supported to be activated per VRF:

1. Under "router bgp/vrfs/vrf" stanza:
   We can use "eos_cli" to configure "default-route export evpn always" for example
2. But, under "router bgp/address_family_evpn/neighbors or peer_groups" stanza, it is not possible to configure "default-route" which is compulsory.

Which component of AVD is impacted

eos_cli_config_gen

Use case example

1. Under "router bgp/VRF":

default-route export evpn always

2. Under "router bgp/address-family evpn":

neighbor <peer_group> default-route

Describe the solution you would like

A possible solution is to add a new Boolean field "default_route" under the elements of the following lists:

• "router bgp/address_family_evpn/neighbors"
• "router bgp/address_family_evpn/peer_groups"

Describe alternatives you have considered

No response

Additional context

No response

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