Fixes in order to restore SaveSearcher temporarily while waiting for rewrite

[SilverBeamx]

This PR addresses some issues that prevent SaveSearcher from properly working. While i know that SaveSearcher is on hold while waiting for the WorldLib rewrite, this PR enables usage for regular users in the meantime. Changes:

• Use "region" folder instead of the root folder to load a dimension
• Look for dimensions folders in any subdirectory (needed for cases such as Advanced Rocketry that use their own custom folder)
• Relax registry regex matcher in order to allow the existance of mod entries with multiple colons in their id (such as Common Capabilities)

[SilverBeamx]

@DaMatrix Sorry for the ping, i don't know if you are still checking notifications for this project. As i stated in the PR description. this changes are mainly aimed at fixing issues i encountered with running SaveSearcher on a 1.12.2 modded savefile. All changes have been tested by rebuilding SaveSearcher against the fixed PorkLib. If you want to i can share with you the save where all these 3 issues were encountered for verification on your part.