Editor: Add Block Bindings API helpers

[gziolo]

Trac ticket: https://core.trac.wordpress.org/ticket/60282

Extracted from #5888. Props to @michalczaplinski and @artemiomorales for most of the work.

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[github-actions]

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[gziolo]

Committed with https://core.trac.wordpress.org/changeset/57375.