Added support for banned items with metadata.

* Added new config option "enable-metrics" to enable/disable.
* Fixed banned items ability to interact with entities.

The config for banned items has been redone for easier user. To ban an
item, set "enable-banned-items" to true then add your banned item/block
IDs to "banned-item-IDs".

Examples:

To ban all ironchests you would add the following:

banned-item-IDs:
 - 975

To ban only Crystal Chests you would add the following:

banned-item-IDs:
 - 975:5