Make end crystals client-side

When on servers, the placing of end crystals are dependent on the player's ping. With higher ping, it takes more time to place, and with lower ping, it takes less time to place. Having high ping can cause a player to have a major disadvantage when playing gamemodes, like crystal pvp, against a player with low ping. This is caused by the end crystal only being registered one it has been placed on the server-side. There are already mods that eliminate this problem, but some servers don't allow them because the would technically be an unfair advantage to players who aren't using these mods, so by making the behavior of these mods the same as vanilla Minecraft, it would give a much preferable experience to high-ping players on servers.