[Feature] Segmentation for build selection

[iwr-redmond]

This FR follows up on the recent EOL announcements for DirectML and IPEX as well as the new preview release for AMD's Strix Halo platform.

Some additional background can be found in my comment here and this Diffusers issue. Note that DirectML supports Torch 2.4.1, not 2.3.1 as I suggested in my earlier comment (DirectML#712).

It may be helpful to be able to segment installable releases into three groups:

• Mainstream
• Preview - e.g. AMD's Windows builds (AMD TheRock Torch builds #17)
• EOL, e.g. 1.x versions of Torch, Torch-DirectML, and IPEX

This would allow developers to error out Torch installation when supporting preview and/or EOL releases is undesirable. By default, Torchruntime could support Mainstream and EOL releases, the current default, with the option to opt-in for preview builds. A unsupported=False type option could then be added to cause a failure on old, mostly unsupported Torch builds. Conversely, a preview=True option could also be added to allow for Torch installation using beta-quality wheels.

[iwr-redmond]

unsupported=False
preview=True

A policy flag might be better:

Policy	Mainstream	EOL	Preview
strict	✅	❌	❌
permissive	✅	✅	✅
allow-eol	✅	✅	❌
allow-preview	✅	❌	✅

You could then have a default alias, which at present would be linked to allow-eol.