Add PhysicsTools/{PyTorchAlpaka,PyTorchAlpakaTest} for heterogeneous and ml

[makortel]

Following cms-sw/cmssw#47984 (comment)

[makortel]

FYI @cms-sw/heterogeneous-l2 @cms-sw/ml-l2

[cmsbuild]

A new Pull Request was created by @makortel for branch master.

@akritkbehera, @cmsbuild, @iarspider, @smuzaffar can you please review it and eventually sign? Thanks.
@ftenchini, @mandrenguyen, @sextonkennedy you are the release manager for this.
cms-bot commands are listed here

[cmsbuild]

cms-bot internal usage

[fwyzard]

+1

thanks @makortel

[smuzaffar]

+externals

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs after it passes the integration tests. This pull request will now be reviewed by the release team before it's merged. @mandrenguyen, @ftenchini, @sextonkennedy (and backports should be raised in the release meeting by the corresponding L2)