Add CI/CD tests using Github Actions.

The tests compile and run the applet in the jcardsim Javacard simulator.
ECDSA signature tests are performed using OpenPGPpy, other tests such as
AES are performed using the local bin/smartpgp-cli script.

TODO: add tests for RSA, asymmetric encryption, pin modifications, secure
messaging (if well supported by jcardsim), etc.

.github/workflows/jcardsim_patches/jcardsim_random_patch

@@ -0,0 +1,20 @@
+diff --git a/src/main/java/com/licel/jcardsim/crypto/SecureRandomNullProvider.java b/src/main/java/com/licel/jcardsim/crypto/SecureRandomNullProvider.java
+index f4cca44..70d41a3 100644
+--- a/src/main/java/com/licel/jcardsim/crypto/SecureRandomNullProvider.java
++++ b/src/main/java/com/licel/jcardsim/crypto/SecureRandomNullProvider.java
+@@ -32,7 +32,14 @@ class SecureRandomNullProvider extends SecureRandom {
+             }
+             @Override
+             protected void engineNextBytes(byte[] arg) {
+-                engine.nextBytes(arg);
++                final String doSecureRandom = System.getProperty("com.licel.jcardsim.randomdata.secure", "0");
++                if ("1".equals(doSecureRandom)){
++                    SecureRandom randomGenerator = new SecureRandom();
++                    randomGenerator.nextBytes(arg);
++                }
++		else{
++                    engine.nextBytes(arg);
++		}
+             }
+             @Override
+             protected byte[] engineGenerateSeed(int len) {