Android Sign v1.7.6

Avoid apk modification when apksigner is used

apksigner tool supports signing an already signed apk thus removing previously present signature files is no longer necessary. We keep this method for jarsigner which fails to sign otherwise. Please note that we reverted from zip to aapt for these removals which reportedly caused large apk sizes for several users. As a thumb rule for apk signing please stick with apksigner and keep jarsigner for signing aab archives.