Support building against llvm15

[yashssh]

Add support for llvmlite to be built against llvm15 while keeping support for llvm14 as well.

1) Drop 2 passes no longer supported by old PM
2) Update domTree passes to their wrapper passes
3) Update getAddress() api
4) Disable opaque pointer mode
5) Give warning when build with llvm15

All the changes are put inside llvm version check guard so that it builds with both llvm14 and llvm15

[yashssh]

Removing draft tag as it won't allow me to add reviewers. Adding "draft" to the title instead.

Edit: Turns out I can't add reviewers. @gmarkall please add yourself and other reviewers who might be interested in this.

[modiking]

LGTM

[gmarkall]

Added "Pending Buildfarm" to make sure this is all OK on all other platforms.

[sklam]

BFID: llvmlite_275

[sklam]

llvmlite_275 passed

[sklam]

Also passed buildfarm test against numba main (numba_yaml_448)