idevice*, iproxy: add pages (#14363)

Co-authored-by: Juri Dispan <juri.dispan@posteo.net>
Co-authored-by: Wiktor Perskawiec <git@spageektti.cc>
Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>

pages/common/idevicebackup2.md

@@ -0,0 +1,20 @@
+# idevicebackup2
+
+> Create or restore backups for devices running iOS 4 or later.
+> More information: <https://manned.org/idevicebackup2>.
+
+- Create a backup of the device in the specified directory:
+
+`idevicebackup2 backup {{path/to/directory}}`
+
+- Restore a backup from the specified directory:
+
+`idevicebackup2 restore {{path/to/directory}}`
+
+- Enable encryption for backups:
+
+`idevicebackup2 encryption on {{password}}`
+
+- List the files in the last completed backup:
+
+`idevicebackup2 list`