Improve remote-reader

[ph4r05]

Several improvements to the remote-reader Android app:

• Refactoring to new Android API (29), bump library versions, Gradle version, use AndroidX classes (removal of deprecated support lib)
• I've added more delay values to the preferences. In my scenario I have card operations that can take longer than 4 seconds (e.g., applet installation can take 6 seconds in my case).
• Listener / reversed mode added

Listener mode

The app now supports Listener mode as VICC supports.

• If enabled, ServerSocket start listening on a VPCD port
• Worker then waits on accept() for a client to connect (accept is timeouted to 1s and repeats with checking for cancellation)
• Once client connects, flow works as with connection mode
• When client disconnects, streams and client socket is closed and worker waits for another connection

I find especially useful that it a smartcard app can open card connection multiple times without need to re-tap card to the phone. I can then run all integration tests with my card tapped to the phone without touching anything.

With original approach when app connects to the VPCD, the card has to be tapped each time VPCD connects.
We are using remote-reader without VPCD, the VPCD endpoint is added as another card connector to our application. Thus separate invocations require more taps.

This PR is a draft, if you want me to change something before merge, hit me up (assuming you are interested in the merge).

Thanks

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May be interesting: I am using this with my personal project https://github.com/ph4r05/remote-card, it contains GlobalPlatformPro wrapper with software-enabled support for VICC (so no vpcd driver install is required). It is possible to manage applets via this GP wrapper over Android remote-reader.

[frankmorgner]

Great, that you found the project helpful. Your changes look good.

I hope the new packages (repositories) are accepted on F-Droid...

[ph4r05]

@frankmorgner I've reverted the default value setting. I forgot to remove it from the PR previously, it was mainly for my personal usage. Now it makes more sense.

Ad F-Droid - hmm I haven't thought about that. Hopefully it works. Should there be a problem I can address that.

Thanks for the review!