kernel: expose umount list to ioctl interface (#2950)

This idea is borrowed from simonpunk's susfs4ksu.
What we see here is that, yeah well, lets just have userspace send us
what it
wants unmounted, this is better than hardcoding everything.

This also solves that issue where MNT_DETACH fails, as long as we send
unmountables in proper order.

A small anti-duplicate mechanism is also added.

While in-kernel umount is a bit worse than zygisk-provider-based ones,
this can still
serve as a healthy alternative.

---------

- Remove duplicate checks

Signed-off-by: backslashxx <118538522+backslashxx@users.noreply.github.com>
Co-authored-by: weishu <twsxtd@gmail.com>
Co-authored-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>

manager/app/src/main/res/values-de/strings.xml

@@ -126,7 +126,6 @@
     <string name="selected_lkm">Wähle LKM: %s</string>
     <string name="save_log">Protokolle Speichern</string>
     <string name="log_saved">Protokolle gespeichert</string>
-    <string name="sus_su_mode">SuS SU-Modus:</string>
     <!-- Module related -->
     <string name="module_install_confirm">das Installationsmodul %1$s bestätigen ?</string>
     <string name="unknown_module">unbekannter Modul</string>
@@ -276,8 +275,6 @@
     <string name="advanced_settings">Erweiterte Einstellungen</string>
     <string name="appearance_settings">Passt die Symbolleiste an.</string>
     <string name="back">Comeback</string>
-    <string name="susfs_enabled">SuSFS aktiviert</string>
-    <string name="susfs_disabled">SuSFS deaktiviert</string>
     <string name="background_set_success">Hintergrund erfolgreich gesetzt</string>
     <string name="background_removed">Eigene Hintergründe entfernt</string>
     <string name="icon_switch_title">Alternatives Symbol</string>