Add bgpkit-broker doctor subcommand

[digizeph]

This PR adds bgpkit-broker doctor subcommand that checks the broker instance status and missing collectors.

Check broker instance health and missing collectors

Usage: bgpkit-broker doctor [OPTIONS]

Options:
      --no-log     disable logging
      --env <ENV>  
  -h, --help       Print help
  -V, --version    Print version

Example output:

checking broker instance health...
        broker instance at https://api.broker.bgpkit.com/v3 is healthy

checking for missing collectors...
missing the following collectors:
| project    | name         | country         | activated_on        | data_url                                           |
|------------|--------------|-----------------|---------------------|----------------------------------------------------|
| routeviews | decix.jhb    | Malaysia        | 2022-12-20 12:00:00 | http://archive.routeviews.org/decix.jhb/bgpdata    |
| routeviews | pacwave.lax  | United States   | 2023-03-30 12:00:00 | http://archive.routeviews.org/pacwave.lax/bgpdata  |
| routeviews | pit.scl      | Chile           | 2023-08-31 23:45:00 | http://archive.routeviews.org/pit.scl/bgpdata      |
| routeviews | amsix.ams    | The Netherlands | 2024-02-22 23:20:00 | http://archive.routeviews.org/amsix.ams/bgpdata    |
| routeviews | pitmx.qro    | Mexico          | 2024-02-23 22:15:00 | http://archive.routeviews.org/pitmx.qro/bgpdata    |
| routeviews | iraq-ixp.bgw | Iraq            | 2024-04-13 00:01:00 | http://archive.routeviews.org/iraq-ixp.bgw/bgpdata |

Resolves #26 #27