Hosted Services updates for 3.0

[guardrex]

Fixes #14381
Fixes #12841

Internal Review Topic

• Whole topic versioning.
• Thanks @manigandham ... In your honor, the official example calls out the VideosWatcher 👀.
• New 3.0 sample.
  • Based on the new Worker Service template, and we can add the VS4Mac instructions now.
  • Nice upgrades to the sample thanks to anurse advice. 💵 In Nurse We Trust™️ 💵 🍻
• Let's drop the 2.x Generic Host sample. That was just a demo (i.e., never linked into the topic), and the Generic Host has churned quite a bit since 2.x. I don't think we should show that at all.
• Let's not have a 3.x Web Host-based sample.

Note: In VSC's external terminal, the sample does respond to keystrokes to add queued work items. However, the app doesn't respond to Ctrl+C. It used to work when the 2.x sample was created and Ctrl+C works in a command shell for this 3.x app, but there's been a VSC regression somewhere along the way. I'll open an issue with VSC to investigate.

[analogrelay]

In Nurse We Trust

[guardrex]

@anurse Update on the Ctrl+C and UseConsoleLifetime situation: I just opened microsoft/vscode#81322. We're ok to proceed on the PR because I tell readers to run the sample app in a command shell. I'm going to open a new issue in a sec connected to that VSC issue to fix this up later when we get a final answer/solution.

[EDIT] Our tracking issue is open now at #14489.

[guardrex]

@anurse Do you still need time to look this over, or should I go ahead and call for docs team review?

[analogrelay]

I think I'm happy with it

[guardrex]

I think I'm happy with it

@anurse I informed our docs management that plausible deniability is an important characteristic of the documentation process that might be used in certain cases where deliberations lead to the apparent need for qualitative distinctions that can't be potentially dealt with under ephemeral circumstances and the underlying complexities of the subject being described can't be completely adjudicated clearly at the time said subject was addressed.

They were very happy with that position and embraced it wholeheartedly. We're all good. 👍

So ......... @Rick-Anderson ... We're ready.