Refactor bootstrap+sandbox into "task" framework

[tmeasday]

Refactor sandbox into yarn task so that it is all of one piece. In particular:

• Remove yarn sandbox turning it into the sandbox task
• Remove yarn bootstrap and ./bootstrap.sh turning them into the compile task
• Documented the above changes and the new recommended workflow

As documented

• yarn start will:
  • Install in code
  • Install in scripts
  • Run the Vite TS sandbox
• yarn task will:
  • Install in scripts
  • Prompt for the task you want to run.

Note that yarn task only installs in code if you choose the install task. If you've never installed, this will definitely happen, but if your install is out of date, this might trip you up. This is documented.

I've tried to get as many places we referenced bootstrap as possible but I'm sure I've missed things. We will definitely need to do more cleanup once we've finished deleting examples.

[ndelangen]

@tmeasday This PR will fix up the cra bench for you:
#19416 (merged)

[ndelangen]

@tmeasday This will fix the netlify check:
#19418

[ndelangen]

@tmeasday I think we could/should change the way we invoke the task from:

yarn task --task compile

to:

yarn task compile

[ndelangen]

I also opened a PR to remove the duplicate yarn installation:
#19417

[tmeasday]

@ndelangen

@tmeasday I think we could/should change the way we invoke the task from:

I agree but I kind of want to merge this. Perhaps a follow up PR later? I was thinking to change the options mechanism to allow certain "positional" options. But we'd also need to tweak all the docs etc.

[tmeasday]

I also opened a PR to remove the duplicate yarn installation:

@ndelangen I ended up doing that in this PR too:cbead1a

[tmeasday]

Oh I see you did something different.