Let users override computed avalanchego_node_json values

[leopaul36]

For now, some properties templated in node.json are computed:

  set_fact:
    bootstrap_ip: "{{ hostvars[groups['bootstrap_node'][0]]['ansible_host'] }}"
  when: avalanchego_network_id == 'local'

- name: Construct public-ip conf
  set_fact:
    node_conf_public_ip: |
      {{ {'public-ip': ansible_host} if avalanchego_static_public_ip else {} }}

- name: Construct bootstrap-* conf
  set_fact:
    node_conf_bootstrap: |
      {{ {
           'bootstrap-ips': '' if inventory_hostname == groups['bootstrap_node'][0]
             else (bootstrap_ip + ':' + (avalanchego_staking_port | string)),
           'bootstrap-ids': '' if inventory_hostname == groups['bootstrap_node'][0]
             else (avalanchego_bootstrap_node_id) 
         } if avalanchego_network_id == 'local' else {} }}

- name: Construct staking-tls-*-file conf
  set_fact:
    node_conf_staking_tls_files: |
      {{ {
           'staking-tls-cert-file': avalanchego_staking_certs_dir + '/' + inventory_hostname + '.crt',
           'staking-tls-key-file': avalanchego_staking_certs_dir + '/' + inventory_hostname + '.key'
         } if avalanchego_staking_use_local_certs else {} }}

- name: Construct http-tls-*-file conf
  set_fact:
    node_conf_http_tls_files: |
      {{ {
           'http-tls-cert-file': avalanchego_https_cert_file,
           'http-tls-key-file': avalanchego_https_key_file
         } if avalanchego_https_enabled else {} }}

We should be able to override these if they are already configured in avalanchego_node_json