Revert "remove hard-coded path to libpinentry, its JNI so it should be found easily"

This reverts commit 70774a84ea229dcd37e9221abdaac9aebd1ee736.
implement key importing from a file in gnupg-for-java
file import activity handles basic import case

the basic case is when it is started with no arguments, so
we assume the user wants to implement any arbitrary file.
send a message when the user clicks "Cancel" in the dialog
when finished with setup, start the MainActivity