Add ozip decryption for Oppo/Realme device

This function will automatically decrypt .ozip file in a .zip and it will
save the .zip in the same folder of the .ozip and with the same name.
After the decryption, the flash will start.

To enable this function you have to set a Boardconfig flag with the
decryption key like i did here:

https://github.com/mauronofrio/android_device_realme_RMX1901/commit/a30625f80a31b9b85e4948fc9f9beeb61d5bcb8a

Original projects:
https://github.com/sabpprook/ozip2zip
https://github.com/bkerler/oppo_ozip_decrypt

Change-Id: Ic93243a565008c442bcf2992069b2801532ac7c1
(cherry picked from commit 0ff59845f2f8dddedb4cee9a9faf86a6294cce66)
diff --git a/gui/theme/common/languages/en.xml b/gui/theme/common/languages/en.xml
index ac9472e..478f88d 100755
--- a/gui/theme/common/languages/en.xml
+++ b/gui/theme/common/languages/en.xml
@@ -724,5 +724,7 @@
 		<string name="unmount_system_err">Failed unmounting System</string>
 		<string name="flash_ab_inactive">Flashing A/B zip to inactive slot: {1}</string>
 		<string name="flash_ab_reboot">To flash additional zips, please reboot recovery to switch to the updated slot.</string>
+		<string name="ozip_decrypt_decryption">Starting Ozip Decryption...</string>
+		<string name="ozip_decrypt_finish">Ozip Decryption Finished!</string>
 	</resources>
 </language>