Add support for AND/ALL option for meta

[sc0ttkclark]

Problem to Solve

When relationships / taxonomies support multiple values, it can be difficult to limit queries by those which contain multiple values saved on those relationships / taxonomies.

Proposed Solution

Support 'AND' / 'ALL' as operators in meta_query

Use similar logic to how tax_query works:

			$num_terms = count( $terms );

			$terms = implode( ',', $terms );

			$where = "(
				SELECT COUNT(1)
				FROM $wpdb->term_relationships
				WHERE term_taxonomy_id IN ($terms)
				AND object_id = $this->primary_table.$this->primary_id_column
			) = $num_terms";

Workaround

No response

Examples Elsehwere

No response

Possible Workaround

No response

Screenshots / Screencast

No response