Drop reference to mildenhall from permissions

Drop references to the old application framework based on mildenhall in
permissions to make it more up to date.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

content/concepts/permissions.md

@@ -351,8 +351,8 @@ metadata fields.
 
 This use-case is only applicable to built-in app-bundles.
 
-A vendor-specific application launcher, such as the [Mildenhall Launcher] in
-the Apertis Mildenhall reference user interface, needs to list all the
+A vendor-specific application launcher, such as the [Maynard] in
+the Apertis reference user interface, needs to list all the
 application entry points on the system together with their metadata.
 It also needs to launch those entry points on-demand.
 
@@ -385,9 +385,8 @@ have public documentation.
 This use-case is probably only applicable to built-in app-bundles.
 
 Suppose a vendor has a [system preferences application] that provides
-an overview of all [system settings], [user settings] and [app settings],
-such as the [Mildenhall Settings] application bundle in the Apertis
-Mildenhall reference user interface. That application needs to list the
+an overview of all [system settings], [user settings] and [app settings].
+That application needs to list the
 app settings belonging to all store and built-in app-bundles, and needs
 the ability to change them, without prompting the user.