This reverts commit 5e862abc23cca1f0f82feb6f174abda0d52db4e5.
Unfortunately this doesn't play nicely with the seeder and needs further investigation. Let's revert in the meantime.
This is not 100% a clean revert:
- We need a few casts in the script_tests to accomodate for the pointer type being reverted.
- The CDataStream constructor from a const uint8_t Span is kept for compatibility with the new code.