Complex sample players placeholders for server list ping

[WouterGritter]

Introduces more complex sample player placeholders and the required parsing plumbing for this.

Example of what's possible to use for motd, motd-hover and fallback-version-ping:

{players:max=16:maxPerLine=8:ordering=ALPHABETICAL:empty=<gray>None:prefix=<yellow>:separator=<gray>, }

where:

• max -> the maximum amount of players to show
• maxPerLine -> the maximum amount of players to show per line
• ordering -> how to order the players:
  • RANDOM -> random shuffle (Notchian behavior)
  • ALPHABETICAL -> A-Z (player name)
  • ALPHABETICAL_REVERSED -> Z-A (player name)
  • LAST_JOINED -> most recent joins first
  • FIRST_JOINED -> oldest joins first
• empty -> what to show when no (0) players are online
• prefix -> the prefix to append before each player name
• separator -> the separator between every two player names (trimmed on line end)

Players are pooled meaning, players won't show up twice. This makes it possible to show the last player that joined, and a random list of all other online players, without this first player showing up in the random list. Example:

motd-hover = [
  "Players: {player-count} / {max-players}",
  "Last join:",
  "{players:ordering=LAST_JOINED:max=1}",
  "",
  "Other players:",
  "{players:ordering=RANDOM:max=6}"]
]

Would show the following MOTD hover:

Players: 100 / 500
Last join:
SomePlayer

Other players:
Notch
jeb_
APlayer
ANotherPlayer
wouterg_
wouterg_too

motd in the config may now also be a string list (similar to motd-hover).

TODO:

• confirm colors are working in placeholder (especially version name)
• config option to ignore "Anonymous Player" toggle on client (isClientListingAllowed)
• config option to pool player list for motd + motd-hover + fallback-version-ping or have one pool per section
• config migration for removed sample-players-in-ping (be smart about this: populate motd-hover based on if this was true/false to avoid changing behavior)
• update config comments. add comments explaining the {players} behavior + argument examples
• update config with sensible defaults (incl. moving motd to a string list)

Example of the PR in action: