added block events

[J3fftw1]

Description

This Pull request gives ways to addons to handle block place/break events from slimefun

Proposed changes

Added ways for addons to handle block place events and block break events.

Related Issues (if applicable)

Checklist

• [x] I have fully tested the proposed changes and promise that they will not break everything into chaos.
• [] I have also tested the proposed changes in combination with various popular addons and can confirm my changes do not break them.
• [x] I followed the existing code standards and didn't mess up the formatting.
• [x] I did my best to add documentation to any public classes or methods I added.
• [x] I have added Nonnull and Nullable annotations to my methods to indicate their behaviour for null values
• [ ] I added sufficient Unit Tests to cover my code.