Feat(eos_cli_config_gen): Add support for radius proxy

[kmueller68]

Enhancement summary

Add support for configuring radius proxy for campus wifi and nac environments.
Radius proxy is available in EOS since 4.31.2F.
https://www.arista.com/en/support/toi/eos-4-31-2f/19037-radius-proxy
https://arista.my.site.com/AristaCommunity/s/article/Deploying-RADIUS-Proxy-on-Arista-Tunnel-Aggregator-Switches

We will start using this function now in two current campus lan & wifi projects on the central tunnel-aggregator VTEP switches.

Which component of AVD is impacted

eos_cli_config_gen

Use case example

radius proxy
   dynamic-authorization
   client key 7 0870151C514A5243445E
   client session idle-timeout 60 seconds
   !
   client group cg1
      client ipv4 1.1.1.1 vrf red
      client ipv4 10.10.10.0/24 vrf red key 7 065F57761A1B5D4A5746
      client ipv6 A:B:C:D:E:F:G:H vrf red key 7 065F57761A1B5D4A5746
      client ipv6 A:B:C:D:E:F:G:H/I vrf red
      client host hostname vrf blue key 7 014254570F5E5058791517
      server group sg1 sg2 sg3

Describe the solution you would like

radius_proxy:
  client_groups:
    - group: <str; unique>
      server_group: <str;	multiple group names separated by space>

      # Encrypted key - only type 7 supported.
      key: <str; optional>

      hosts:
        # Hostname
        - host:  <str; unique>
          vrf: <str; required>
          # Encrypted key - only type 7 supported.
          key: <str; optional>

      prefixes_ipv4:
        # IPv4 address "A.B.C.D" or prefix "A.B.C.D/E"
        - prefix: <str; unique>
          vrf: <str; required>
          # Encrypted key - only type 7 supported.
          key: <str; optional>

      prefixes_ipv6:
        # IPv6 address "A:B:C:D:E:F:G:H" prefix "A:B:C:D:E:F:G:H/I".
        - prefix: <str; unique>
          vrf: <str; required>
          # Encrypted key - only type 7 supported.
          key: <str; optional>

  # Encrypted key - only type 7 supported.
  client_key: <str>

  client_session_idle_timeout: <int; 1 - 86400 seconds>

  dynamic_authorization: <bool>

Describe alternatives you have considered

eos_cli does the job but it's not pretty.

Additional context

No response

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