Fix #98 and #26 + other changes

[srnyx]

Description

• Send /broadcast to Discord too
• Add /bc as alias to /broadcast
• Fix undeads always being able to talk
• Add undead Discord join/leave messages
• Made cooldown message configurable
• Added isLinked to LinkManager.java
• Added getOfflinePlayerTeam to TeamManager.java
• Added Discord to Minecraft chatting
• Got rid of duplicate if statement
• Added boat material list
• Compile PaperMC
• Prevent grindstoning and anviling Lock Tool
• Fixed AFK invulnerability
• Doors can now be locked!
• DM discord.chat-fail

Motivation and Context

• Fixes #26
• Fixes #98

How Has This Been Tested?

Tested on GeekSMP Development server.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [x] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [x] I have read the CONTRIBUTING document.
• [x] All new and existing tests passed.