Replace HubBalancer with a more broad "serverbalancer" system.

[dieterblancke]

Configuration may be like so:

balancers:
    # The server group to balance in, any time someone joins a server from this group, BuX will attempt to balance this out.
  - group: Lobbies
    # There are 4 methods available: RANDOM, LEAST_PLAYERS, FIRST_NON_FULL, MOST_PLAYERS. LEAST_PLAYERS is recommended.
    method: LEAST_PLAYERS

    pinger:
      # The delay, in seconds, between BuX pinging servers to check if they are accessible.
      delay: 5
      # Maximum attempts until BuX will stop pinging the server for {cooldown} seconds (see below)
      max-attempts: 3
      # If the maximum attempts have been reached and the server is still offline, how long should BuX not try to ping the server?
      cooldown: 60

    # Can be left out, a command to teleport to a random server in this specific balanced group.
    command:
      enabled: true
      name: 'hub'
      aliases: 'lobby'
      permission: bungeeutilisalsx.commands.hub
      listener-based: true

    # The server group to balance in, any time someone joins a server from this group, BuX will attempt to balance this out.
  - group: minigames-walls
    # There are 4 methods available: RANDOM, LEAST_PLAYERS, FIRST_NON_FULL, MOST_PLAYERS. LEAST_PLAYERS is recommended.
    method: MOST_PLAYERS

    pinger:
      # The delay, in seconds, between BuX pinging servers to check if they are accessible.
      delay: 5
      # Maximum attempts until BuX will stop pinging the server for {cooldown} seconds (see below)
      max-attempts: 3
      # If the maximum attempts have been reached and the server is still offline, how long should BuX not try to ping the server?
      cooldown: 60
      # Only have servers as "connectable" if they meet the following rules
      motd-filter:
        - '(?i).*Waiting ...*'

    # Can be left out, a command to teleport to a random server in this specific balanced group.
    command:
      enabled: true
      name: 'hub'
      aliases: 'lobby'
      permission: bungeeutilisalsx.commands.hub
      listener-based: true

fallback:
  type: 'BLACKLIST'
  reasons:
    - 'ban'
    - 'kick'
  fallback-to: Lobbies

[dieterblancke]

Initial implementation this in BungeeUtilisalsX v2.4.0 development build as of now, with a config similar to the one above.