If Sonarr is behind a reverse proxy with a custom URL Base setting, the sonarr_list plugin wouldn't work because it doesn't support a custom base path. This should fix that.

Motivation for changes:

• Can't use sonarr_list with my Sonarr setup (custom base path with reverse proxy)

Detailed changes:

• Added base_path config schema option to sonarr_list with default value of '' (should be backwards compatible)

Config usage if relevant (new plugin or updated schema):

tasks:
  task-name:
    sonarr_list:
      base_url: https://server.example.com
      port: 8443
      base_path: /sonarr
      api_key: ...

This example config will use https://server.example.com:8443/sonarr/api/ as the base API path.