Feature: Add config support for servers.yml

[glensc]

Currently only "sync" command reads "sync" settings.

servers:
  default:
    id: xxx
    token: xxx
    urls:
      - https://xxx.plex.direct:32400
    config:
      sync:
        plex_to_trakt:
          collection: true
        trakt_to_plex:
          liked_lists: false