tidy up authtype setting class (incl. fix issue with auth change/logoff occurring when only one auth plugin is enabled and other settings are updated)

FS#2111, improve security check

Add django compatible hashes to the config options.

This prevents old requests that need longer than the newer ones (likely,
as if you type more less results are returned) from overriding the
results list.

Previously the media manager created an empty namespace whenever you
opened a non-existing namespace with upload permissions. Now the current
namespace is only displayed in the tree but not actually created.

this disables the JavaScript compatibility layer which let pre-jQuery
migration plugins run with their old code.

This will break plugins using outdated JavaScript. These plugins have to
be updated according to https://www.dokuwiki.org/devel:jqueryfaq

As a courtesy to users, the compatibility.js is not deleted, yet.
Undoing this single patch can be used as a temporary workaround.

It seems, some servers require a special Status: header for sending the
HTTP status code from PHP (F)CGI to the server. This patch introduces a
new function (adopted from CodeIgniter) for simplifying the status
handling.

This deprecates the "richemail" config class

store choices for recent changes and diff views in cookie

failed because of the rename of auth_basic