add enhanced privacy

[PeterRounce]

related issue boltcard/boltcard#21

With app v0.1.2 (bd0f5ec) it is possible to write and wipe cards from the bolt card service that includes the uid_privacy flag because it is ignored by the app.

The bolt card app enhancements should be implemented without affecting the LNbits bolt_card extension until that is ready to adopt the enhanced privacy updates.

The app should detect create_bolt_card_response v2 when it has uid_privacy set to Y
It should then authenticate with the card and set PICCConfig.UseRID=1
The UID will be random or zero after a card power cycle

In my testing, I've noticed this message when UseRID is set and the create card tests are run.

Also the Card UID shown is random and it is easily detectable as the value is shorter than the previous static value.
Perhaps we should show Card UID: private instead

[PeterRounce]

The TapLinx method to activate the 'random UID' feature is:

https://www.mifare.net/developer/javadoc/android/
Interface INTAG424DNA
void setPICCConfiguration(boolean enableRandomUID)

[robertclarkson]

added this feature to test branch https://github.com/boltcard/bolt-nfc-android-app/tree/random-uid

[PeterRounce]

all works except.. issue #29