This reverts commit 91e9c1c81343990d5ebbb3a3bb7c68ec4445d610.
After feedback, for now we are reverting this change. This is not
permanent, the settings sidebar will be removed again, after we:
* Visually group the settings the same way as the sidebar does
on All Settings
* Add more settings pages to the main admin sidebar to cover the ~250
settings not yet represented there
This experiment hides the list of categories in the inner
sidebar for the main site settings page if the admin sidebar
is enabled. It also defaults the list of settings to "All"
instead of a specific category.
Our theory here is that people who use this page are using
it to find an exact setting, not to go through the categories
one by one. Our admin sidebar also has several groups of important
settings already too, so that can be used for browsing.
Finally, the input on the page focuses when you load it, so
filtering is faster.
