EXP: packing / unpacking of android backups

[DonatJR]

copy of issues these changes have:

// WARNING: this currently uses a external tool (abe.jar) to extract the android backup
// to files, this is because there is (at the moment!) no suitable rust crypto crate which we can use for this, see: 
// https://github.com/briansmith/ring/issues/573 and https://github.com/briansmith/ring/issues/588
// DANGER: also, the tar crate is not able to extract files from archives which have invalid file names on the current OS,
// as a result of this a few files from every backup get lost irrevocably -> the file extraction should not be used before this is fixed
// (=> create a PR in the tar crate, possible solution: vector / map with chars that need a replacement char on current OS)