[9.0.2xx] sln migrate, sln list, sln add

[edvilme]

Manual backport of #44419 , #44537 , #44661 #44570, #45130, and #45366 to release/9.0.2xx

Fixes #40913.

[kasperk81]

@edvilme source-build-ext update for 9.0.2x requires kasperk81@c713864

[marcpopMSFT]

@baronfel we should get this reviewed tomorrow and merge so that it can get into the next VS insertion for preview 3.

[Forgind]

Content-wise, I glanced through the commits, and they looked equivalent to what was merged as I'd expected, but it's essentially a whole new set of commits, which I don't like too much. I would've hoped for at least some of them to not be in need of resolving merge conflicts, especially if you tweak it to look as the next commit would expect in earlier commits...but I probably shouldn't nitpick on that right now. You can make that a little easier too by making sure all your commits are in order, which you mostly did except one that got moved out of place 😉

[kasperk81]

this should include #45160 and "fix #40913" in description so the downstream consumers get some time to enable slnx in 9.0.200 timeframe

[baronfel]

Since the only failing checks are due to the macOS arm64 leg, let's merge on read and get this in! @marcpopMSFT care to do the honors?

[marcpopMSFT]

Content-wise, I glanced through the commits, and they looked equivalent to what was merged as I'd expected, but it's essentially a whole new set of commits, which I don't like too much. I would've hoped for at least some of them to not be in need of resolving merge conflicts, especially if you tweak it to look as the next commit would expect in earlier commits...but I probably shouldn't nitpick on that right now. You can make that a little easier too by making sure all your commits are in order, which you mostly did except one that got moved out of place 😉

We can give pointers when he's back in the office as there are some strategies for avoiding merge conflicts especially in our repo (target the live branch and let codeflow take to main as an example).

[marcpopMSFT]

We'll get remove in once it passes checks.