Adds support for Minecraft 1.17, make sure to update BKCommonLib! As well, fixes the following things:

• Removed world load retry count - caused true failures to load to be swallowed up, causing confusion. Plus, what's the point?
• Fix mob effect casting bug
• Add default nether link on forge servers, where world name is dim-1/dim1/etc.
• (Attempt to) load the spawn area asynchronously when creating a new world. At least reduces the lag that happened before.