feat: add netbox input

[ShimmerGlass]

Overview

This new Netbox Input class loads and refresh prefixes to monitor dynamically from Netbox's IPAM.

It automatically sets the prefix description from Netbox data so operators can quickly identify what prefix is affected when an alert pops up.
Prefixes are periodically refreshed to ensure BGPalerter works on up to date data.

This implementation makes no assumption about how data is organized in Netbox and instead lets users configure querie(s) via any parameter exposed by Netbox's REST API to find the appropriate prefixes they wish to monitor.

Example config

inputNetbox:
  url: https://netbox
  token: [TOKEN]
  refreshIntervalSeconds: 300
  queries:
    - params:
        description__iew: EUROPE PUBLIC IPV4
      asn:
        - 12345
    - params:
        description__iew: EUROPE PUBLIC IPV6
      asn:
        - 12345
    - params:
        description__iew: ASIA PUBLIC IPV4
      asn:
        - 67890
    - params:
        description__iew: ASIA PUBLIC IPV6
      asn:
        - 67890

Documentation

Documentation is not yet updated. I would first like the scope of this PR and the configuration format be validated before tackling that part.