Remove the warning system

Warnings were a moderator tool layered on top of reports and had no
callers left outside their own command and the player list button. The
legacy module, its config and locale, the exp_scenario command and its
permissions, the discord alert block and the player list button are all
removed. Reporting from the player list no longer depends on whether the
player could give warnings, anyone can report a player who is not immune.

exp_scenario/module/control.lua

@@ -38,7 +38,6 @@ require("modules/exp_scenario/commands/surface")
 require("modules/exp_scenario/commands/teleport")
 require("modules/exp_scenario/commands/trains")
 require("modules/exp_scenario/commands/vlayer")
-require("modules/exp_scenario/commands/warnings")
 require("modules/exp_scenario/commands/waterfill")
 
 --- Control