Correct PhysX attribution metadata

Verified the bundled PhysX copy against upstream by comparing git blob
hashes of all 1214 files with the NVIDIAGameWorks/PhysX trees. The
content is PhysX 4.1.2.29882248 plus the patches stored in this
directory; every locally modified file is accounted for by one of them.

Three corrections follow from that:

- DownloadLocation pointed at commit 93c6dd21, which is the earlier
  build 4.1.2.29873463. The shipped DyTGSContactPrep.cpp matches the
  4.1.2.29882248 blob, so point at commit c3d5537 instead.

- Copyright listed only NVIDIA. The sources carry three notices:
  NVIDIA (2008-2021), AGEIA Technologies (2004-2008) and NovodeX AG
  (2001-2004). List all three, here and in REUSE.toml.

- Drop the PhysX_ prefix from Version so it matches upstream
  version.txt, and add a PURL, which this package lacked despite being
  marked SecurityCritical. No CPE is added: the NVD dictionary has no
  entry for the PhysX SDK, only nvidia:physx_system_software, which is
  the Windows driver runtime and a different product.

[ChangeLog][Third-Party Code] Corrected the recorded upstream commit,
copyright holders and version string of the bundled NVIDIA PhysX SDK,
and added a PURL for SBOM generation.

Pick-to: 6.8 6.11 6.12 6.12.0
Change-Id: I6ade87aa429fbdc9ad6709d1ac96ae61534432bd
Reviewed-by: Jonas Karlsson <jonas.karlsson@qt.io>