Add ability to not change display names for NPCs

[marlester-dev]

Feature description

If essentials changes displayname or tablistname the event will detect it. Make it cancelable.
I want to stop essentials from changing displayname and tablistname of my (specific fake) plugin's players.

How the feature is useful

It will help me to make my plugin compatible with essentialsx.
Just changing change-displayname and change-playerlist to false is bad solution because I need essentials to stop changing displayname and tablistname of my (specific fake) plugin's players and not all players, I can't do it with standard api, correct me if I'm wrong.

[JRoy]

I think a better solution would be to add an option to not change the display names of players with NPC metadata, events for this would be too clunky

[yiqimomoyu]

I'm having the exact same issue.