Allow execution of specific notebooks to be skipped

[choldgraf]

Currently it's possible to tag specific cells for skipping execution (with skip-execution) but there's not a way to do this for entire notebooks. It would be useful if this were possible either in page metadata, or in a list of exclude glob patterns in myst.yml.

This is useful when you have:

1. A notebook that you know is broken, and so you don't want to clog up your build with broken execution
2. A notebook that takes a lot of resources to build, and you want to run it once and embed the outputs inside without re-executing

[agoose77]

In JB1 there's support for per-notebook execution (c.f. https://jupyterbook.org/en/stable/content/execute.html#exclude-files-from-execution). We should allow opt-out on a per-notebook basis, in addition to a broader solution regarding execution strategies!

[agoose77]

In order to tackle this, I'm going to be refining #1373 and #1498. The reason for this is that the present configuration situation is confusing, and with the new launch button, we need to start planning our way out of the mess!

[rowanc1]

Do we have the bandwidth to expand the scope of this issue at the moment? I agree the settings object needs to go through an iteration to improve it. That could also happen after JB beta is out.

[agoose77]

Do we have the bandwidth to expand the scope of this issue at the moment? I agree the settings object needs to go through an iteration to improve it. That could also happen after JB beta is out.

Yes to refine, no to "do".

I want to do enough refinement that the shape of the frontmatter (and other consequences) in this PR are compatible with those future changes. I anticipate this will not take too long.

[rowanc1]

Ok - misunderstood that you were bringing those changes into scope to complete before/during this feature. Your proposal is making sure we are forward compatible with those proposed changes. Makes sense, thanks for clarifying.