[Website] Improve error reporting

[adamziel]

Motivation for the change, related issues

Replaces the small "report error" modal with a large modal providing useful error information in multiple error scenarios:

The new modal provides:

• An action button (typically to restart Playground without the Blueprint).
• A "report error" button on Playground crashes (but not on Blueprint execution errors).
• The relevant Blueprint fragment for some types of schema validation errors.
• The overview of the failed Blueprint step when execution fails.
• The unreachable Blueprint URL when Blueprint resolution fails.
• A short explanation (for some errors).
• A link to the documentation (for some errors).

This PR also:

• Displays the address bar if WordPress boots but the Blueprint execution fails.

Testing Instructions (or ideally a Blueprint)

Trigger the modal in different error scenarios:

• Plugin cannot be installed
• Blueprint validation error
• Blueprint syntax error
• Invalid ?blueprint-url
• Valid ?blueprint-url with a non-Blueprint response
• Bundled resource used with a non-bundled Blueprint