Enable a sample-first development experience for new packages

[xirzec]

Today authoring samples is very difficult (no good IntelliSense) and is oriented towards providing content that will work on docs.microsoft.com.

However, it is very useful for a library author to be able to interactively build up a sample program while they are testing out and designing their new client. As such, I'd like to accomplish the following:

1. A library author can easily create a new local-only sample that they can build against their in-development package (and later turn into a "real" sample to publish.)
2. IntelliSense/authoring should work just as it would in the final package.
3. Running the sample (e.g. from a VS Code task) should be easy and include the ability to debug via breakpoints.

This will put us on-par with other languages (e.g. C#) in allowing library authors to get a sense of the developer experience they will be providing to customers, even before their library is fully functional/implemented.

[ramya-rao-a]

@willmtemple Do we see an overlap between this issue and #7651 and
#10334 ?

[willmtemple]

@ramya-rao-a Yes. One very simple way that we could enable a better experience than we have now is if we can set up a post-install hook using Rush to link the samples to the development package. This is what I do locally on my development machine with dev-tool samples dev, which creates a symlink that allows samples to resolve the package.

With a more fully-featured samples management process, we can make it work out of the box by keeping the samples in the tsconfig project tree. If we do that, then we can also debug them using the same settings as for tests and package code. This is effectively what C# does, but they don't publish their samples as source code projects like we do, and they don't have to support two languages like we do. We will have to do a little more work to move things around and keep them in the right shape.

[xirzec]

I feel like the current sample authoring experience is pretty good now. @willmtemple is there anything we still need to do here?

[witemple-msft]

@xirzec closing, as new packages should be able to easily start with samples.