AMDGPU {NFC}: Add code object v5 support and generate metadata for implicit kernel args

Summary:
  Add code object v5 support (deafult is still v4)
  Generate metadata for implicit kernel args for the new ABI
  Set the metadata version to be 1.2

Reviewers:
  t-tye, b-sumner, arsenm, and bcahoon

Fixes:
  SWDEV-307188, SWDEV-307189

Differential Revision:
  https://reviews.llvm.org/D118272