Implement: when tapped, the apks in a repository should start the app installation

[IvanaBlzvc]

Tested with 0.7.8

Steps to reproduce

• Import an apk into ouisync repository (android device 1)
• share that repository as read only with another device (android device 2)
• in the device 2, tap on the apk

Expected results

• the tap should bring up the dialog box asking the user if they want to install this app
• when the user taps Yes, the install process should run

Actual results

• when the user taps the apk within a ouisync repo, nothing happens.