Allow Placement of wildcards in meta query like (meta.php WP_Meta_Query)

[Will B]

The LIKE comparison has '%' hardcoded before and after the value (meta.php line 807)

$meta_value = '%' . like_escape( $meta_value ) . '%';

Being able to specify the placement of the wildcards would be helpful
(maybe starts with and end with kinda queries). before and after could be the default.

$meta_value = '%' . like_escape( $meta_value ) . '%'; // default

$meta_value = like_escape( $meta_value ) . '%'; // starts with

$meta_value = '%' . like_escape( $meta_value ); //ends with

[SergeyBiryukov]

Duplicate of #19738.