Add search and links to plugin settings (#4854)

* Show links to plugin views and settings in plugin list and in success message after activating a plugin
* Fix menu highlighting in payment provider settings
* Specify settings_links and navigation_links for built-in plugins
* Add link to payment plugins from payment settings
* Add client-side search and "View only active plugins" for plugins page

doc/development/api/plugins.rst

@@ -84,6 +84,8 @@ A working example would be:
             restricted = False
             description = _("This plugin allows you to receive payments via PayPal")
             compatibility = "pretix>=2.7.0"
+            settings_links = []
+            navigation_links = []
 
 
     default_app_config = 'pretix_paypal.PaypalApp'
@@ -185,6 +187,28 @@ your Django app label.
    with checking that the calling user is logged in, has appropriate permissions,
    etc. We plan on providing native support for this in a later version.
 
+To make your plugin views easily discoverable, you can specify links for "Go to"
+and "Settings" buttons next to your entry on the plugin page. These links should be
+added to the ``navigation_links`` and ``settings_links``, respectively, in the
+``PretixPluginMeta`` class.
+
+Each array entry consists of a tuple ``(label, urlname, kwargs)``. For the label,
+either a string or a tuple of strings can be specified. In the latter case, the provided
+strings will be merged with a separator indicating they are successive navigation steps
+the user would need to take to reach the page via the regular menu
+(e.g. "Payment > Bank transfer" as below).
+
+.. code-block:: python
+
+        settings_links = [
+            ((_("Payment"), _("Bank transfer")), "control:event.settings.payment.provider", {"provider": "banktransfer"}),
+        ]
+        navigation_links = [
+            ((_("Bank transfer"), _("Import bank data")), "plugins:banktransfer:import", {}),
+            ((_("Bank transfer"), _("Export refunds")), "plugins:banktransfer:refunds.list", {}),
+        ]
+
+
 .. _Django app: https://docs.djangoproject.com/en/3.0/ref/applications/
 .. _signal dispatcher: https://docs.djangoproject.com/en/3.0/topics/signals/
 .. _namespace packages: https://legacy.python.org/dev/peps/pep-0420/