* Reverting changes in https://github.com/woocommerce/woocommerce/pull/30380, preparatory to merging the My Subscriptions and Marketplace pages back into one Extensions page.
* Moved category nav to a separate file.
* Added main nav tabs.
* Added category nav, styled the mobile version.
* Experiments with doing category tabs as a list.
* Styling category menu as a list of links in rectangular pills on desktop.
* Adjusting margins of product list in in-app marketplace.
* Removed `submenu_file` filter which called deleted `update_menu_highlight` method.
* Restored styling for update count bubble on My Subscriptions tab.
* Styling update bubble on My Subscriptions tab.
* Addressing design feedback. Restyled category pills to make them more obvious. Added `Browse categories` title before category menu on desktop. Changed `.addon-product-group-title` to an h2.
* Addressing feedback from https://github.com/woocommerce/woocommerce/pull/31085#pullrequestreview-806319880.
- Removing addition of `admin_title` filter calling deleted `update_my_subscriptions_title` method.
- Prepending `__DIR__` constant before path in `require` call.
* Removed Changlogger Autoload
* Changed Jetpack Changelogger Formatter Loading
Rather than using the Composer autoload, we should use the
changelogger's "filename" option to point directly at the file.
This keeps the file out of the autoloads, since it's possible that
plugins or packages may be symlinked and break the relative
path to the plugin.