Update to some newer Terramap features

[SmylerMC]

Changes:

• Shade Bungee2ForgeChannels instead of implementing Forge simple channels in Sledgehammer itself.
• Changed all code referring to "Terramap Addon" to "Terramap Module".
• Support for the newer Terramap version schema (that includes the Minecraft version).
• Support for the newer map style configuration options:
  • Support for setting the client's max concurrent connection when downloading map styles.
  • Support for multiple URL patterns to allow fetching a single map style from multiple servers at once.
  • Support for marking map styles as 'debug' (are ignored by clients unless their debug option is enabled) Some features added in the development versions of the client mod are not supported here (mainly map styles bounds).

Tested features:

• [x] Global map setting
• [x] Network wide map saving
• [x] Cross server player synchronization
  • [x] Basic
  • [x] Skins
  • [x] /terrashow command
• [x] Custom map styles