Add FlatterScatter creation policy

[chillenzer]

This is WIP and the original description here is horribly outdated. I'll keep this in for easy access to the diff but I'll update once it's relevant.
Hi @psychocoderHPC,

this version has a compile-time defined heap. Should theoretically work as almost drop-in replacement for the old version with the following changes:

• wastefactor == 1 and resetfreedpages == true are enforced at compile-time.
• The ScatterConfig struct used to configure the heap needs one more compile-time value heapsize.
• There is a runtime value for heapsize given to the constructor of the Allocator. The two are enforced to be identical.

Feel free to play around with it!