UserBanEvent and UserPardonEvent

[Zkir]

Feature description

Add the new events: UserBanEvent and UserPardonEvent, which should be raised when user is banned or pardoned via essentials /ban or /pardon (/unban) commands respectively.

Those events will be similar to the UserKickEvent, with the difference that those events will be called for offline players (UserKickEvent is raised only for online player, but a player who is currently offline can be banned also, and obviously only offline player can be pardoned).

P.S.
The feature seems to be quite easy to implement (2 new event classes and 2 lines of code to call them).

How the feature is useful

Those events will be useful for plugin developers who need to monitor administrative actions.

In my project I need to send instant messages to inform banned/pardoned players to inform them about their status (on our server offline players often get banned, when moderators find results of their misbehavior, and also to display the log of moderator actions on our site.

[Zkir]

Possible solution can be like this. A bit longer then 2 lines of code, but still.

Cosmetic change to existing code: banned or pardoned player is called target, command sender is called user, as in existing kick command.