Chunk-Pregenerator

Hotfix/Critical Bugfix patch for a bug that was found a couple times but it took a long time to find out what the issue was.

NOTE: This affects every single pregenerator that I know of and that includes a lot of them.

So whats the problem: 

A pregenerator loads a chunk makes sure that its fully generated then unloads it. (It loads extra chunks as needed for this specific chunk)

Now the default implementation is they load a 4x4 grid area.

There is a extra step that has to be done otherwise not strongly powered servers will have giant lag problems.

This extra step is lighting the chunks which only happens if a chunk is in the center of a 3x3 chunk area otherwise the step outright will be skipped.

This patch fixes this issue. By a newly designed pregenerator that accounts for this problem in the first place.

The pregenerator does basically work the same but has a new foundation so stability should be 95-99% instead of the 99% the 2.4.1 release has.
On top of that the pregnerator seems to have gotten a 10-20% pregen speed boost due to the new foundation logic.

Changelog:

Version 2.5.0:

- Changed: Reworked the Entire Pregeneration logic to fix the "chunklighting" step missing.

- Added: The Max Pregeneration radius got changed from 1000 to 25000 due to new Pregeneration Task "A LOT" taking less memory then 2.4.1 version. (Thanks 1.14-1.16)

- Added/Fixed: Pregenerator now prepaires tasks offthread allowing for much larger tasks to be started without crashing. This also fixes the constant crashloop when the task was to big. (Thanks 1.14-1.16)

- Changed: Tasks no longer skip chunks during runtime they are now skipped during task creation allowing for a more accurate pregen task size. (Thanks 1.14-1.16)

- Fixed: Preview sees chunks now as they are being generated allowing for a much better view. (Think: TerrainOnly view got also now applied to fullgen view) (Thanks 1.14-1.16)

- Changed: Preview Converts chunks now to PreviewChunks on the ServerThread. This should fix a lot of incompats with the Preview. (GT6 is now compatible with it confirmed)

- Fixed: Bug with a Networking Packet for Deletion Tasks.

- Added: Config to Delete Structure References during pregeneration to fight the memory leak.