Option to set data folder path

[drws]

Is your feature request related to a problem? Please describe.
Some users might want to be able to set the data folder path from the default com.fr3ts0n.ecu.gui.androbd in the root of the user's data folder.

Describe the solution you'd like
A setting for custom data folder path.

Describe alternatives you've considered
Symlinking would work on a real Linux system, but the link would still "litter" the home folder.