Implement banning API. Adds BUKKIT-3535

Previously no implementation existed to access various additional
information fields regarding bans. This implementation expands on the
information outlined in the sister Bukkit commit to provide access to
the Minecraft implementation of the ban system.

This implementation of the banning API contains 2 new classes which
provide access to the internal workings of the built-in banning
system within Minecraft.

The CraftBanEntry class simply supports the representation of an internal
Minecraft BanEntry object. The data that may be modified within this new
object must be manually saved to the list contained within the
CraftBanEntry using it's save() method.

The CraftBanList class supports the representation of an internal
Minecraft BanList object through proxy methods. These methods do
validation on the passed objects where needed to ensure safe input to the
backed Minecraft objects.

These changes additionally re-route the existing banning API to the newer,
more detailed, system. Functionality prior to this change still behaves
as documented by the contract defined by the methods changed.
[Bleeding] Implement Mojang command fallback system. Adds BUKKIT-5385
Match old alias behavior when migrating.

Previously the alias system would pass all arguments from the alias
to its command(s) implicitly. The new system requires arguments to be
explicitly passed so server owners can have more control over where and
how they are passed. To ensure this isn't a breaking change during the
migration from bukkit.yml to commands.yml we now add the $1- argument
to the alias commands to match the previous behavior.