New app: OAndBackupX

• The app complies with the inclusion criteria
• The original app author has been notified (and supports the inclusion): if this means the forked app Author
• All related fdroiddata and RFP issues have been referenced in this merge request: no related issues opened
• The upstream app source code repo contains the app metadata (summary/description/images/changelog/etc) in a Fastlane or Triple-T folder structure: with neither apps specifically but has their standard file layout
• Builds with fdroid build: not tested*
• Releases are tagged

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*The build script for the most part is the same as the old OAndBackup(only updated the needed versions of NDK and Rustup), so it should work the same.

closes rfp#1316 (closed)