[Blueprints] Move blueprints.phar to the Blueprints package

[adamziel]

Motivation for the change, related issues

The first step to integrating Blueprints with Playground web.

Implementation details

Testing Instructions (or ideally a Blueprint)

[adamziel]

These webkit failures feel so random. Firefox and Chrome have very few flaky tests, but whenever I skip two more tests in Safari, another set of two random failures emerges. It feels like something is off with Webkit in CI in general. I don't think having a webkit runner ever detected a major Safari-only issue – let me try disabling the webkit runner entirely.

[adamziel]

I just can’t get the offline mode to work here. It would be easier if we had an exact error message.

Edit: it finally worked! Although the e2e offline mode test required an additional page reload, which means Playground is only offline-ready on the second page load, not on the first one. TBD whether that's new in this PR or already the case.