Block Bindings: Bootstrap block bindings sources with inline script from server

[SantosGuillamot]

Fixes the issue reported here: WordPress/gutenberg#66031

Basically, we need to ensure the bootstrap happens early in the process to ensure extenders code runs after it. The current implementation runs after domReady which seems to be too late.

In this pull request, I propose changing the approach and using an inline script like we are doing for bootstrapping block types.

Trac ticket: https://core.trac.wordpress.org/ticket/62225

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Props santosguillamot, cbravobernal.

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[github-actions]

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[cbravobernal]

Works as expected. Still needs the track ticket to be complete.

[SantosGuillamot]

Still needs the track ticket to be complete.

I have just created the ticket: https://core.trac.wordpress.org/ticket/62225#ticket

[gziolo]

Committed with https://core.trac.wordpress.org/changeset/59238.