Add missing configuration documentation

[mdsimmo]

What problem does the feature solve
Documentation on the following features is lacking:

• How to use bm configure
• All bomberman players have bmplayer nbt tag
• Tools can be configured to break specific blocks
• Blocks can be configured to be only placed on certain blocks

Describe the solution you'd like

Document it!

Describe alternatives you've considered

Ignore the problem and let users be confused