REST API: Bring new endpoints for Block Patterns from Gutenberg plugin

Related Gutenberg issue: https://github.com/WordPress/gutenberg/issues/39889.

Backporting changes from the Gutenberg plugin:
- new Block Patterns REST API endpoint
- new Block Pattern Categories REST API endpoint
- updates to Query Loop related patterns
- support for custom taxonomies in Query Loop block

Props hellofromtonya, peterwilsoncc, ntsekouras, zieladam, ironprogrammer, spacedmonkey, timothyblynjacobs, antonvlasenko, jsnajdr.
See #55505.



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git-svn-id: http://core.svn.wordpress.org/trunk@52741 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/block-patterns/query-grid-posts.php

@@ -9,7 +9,7 @@ return array(
 	'title'      => _x( 'Grid', 'Block pattern title' ),
 	'blockTypes' => array( 'core/query' ),
 	'categories' => array( 'query' ),
-	'content'    => '<!-- wp:query {"query":{"perPage":6,"pages":0,"offset":0,"postType":"post","categoryIds":[],"tagIds":[],"order":"desc","orderBy":"date","author":"","search":"","exclude":[],"sticky":"exclude","inherit":false},"displayLayout":{"type":"flex","columns":3}} -->
+	'content'    => '<!-- wp:query {"query":{"perPage":6,"pages":0,"offset":0,"postType":"post","order":"desc","orderBy":"date","author":"","search":"","exclude":[],"sticky":"exclude","inherit":false},"displayLayout":{"type":"flex","columns":3}} -->
 					<div class="wp-block-query">
 					<!-- wp:post-template -->
 					<!-- wp:group {"style":{"spacing":{"padding":{"top":"30px","right":"30px","bottom":"30px","left":"30px"}}},"layout":{"inherit":false}} -->