Networks and Sites: Revert the use of the metadata API for *_network_options functions.

[54080] refactored the logic in `get_network_option()`, `update_network_option()` and `delete_network_option()` to use the metadata API. However, this change resulted in issues with large multisite installs that utilize memcached having network options > 1MB in size.

This change reverts [54080] and all related follow-up changes.

Reverts [54080], [54081], and [54082].  Partially reverts [54267] and [54402].

Props pavelschoffer, rebasaurus, johnbillion, spacedmonkey, desrosj, rinatkhaziev.
Fixes #56845.
See #37181.
Built from https://develop.svn.wordpress.org/trunk@54637


git-svn-id: http://core.svn.wordpress.org/trunk@54189 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/load.php

@@ -743,7 +743,6 @@ function wp_start_object_cache() {
 				'site-details',
 				'site-options',
 				'site-transient',
-				'site_meta',
 				'rss',
 				'users',
 				'useremail',