View configuration API: fix versioning

Rework the WP_View_Config_Data write API around merge(), replace(), set(), and remove(), all operating on patches of top-level keys and taking the schema version the change was authored against. Make get_data() private and move filter application into a new apply_filters() method so callbacks cannot read the materialized configuration and become coupled to its shape. Update the default post type configuration callbacks to use the new single-patch set() signature. Adapt and expand the unit tests accordingly.

Props oandregal, jorgefilipecosta, ntsekouras, t-hamano.
Fixes #65577.






git-svn-id: https://develop.svn.wordpress.org/trunk@62825 602fd350-edb4-49c9-b593-d223f7449a82

Author: oandregal