psa: programs: Add cipher example

Add `programs/psa/crypto_examples.c`. Update relevant Makefiles,
CMakeLists.txt, and .gitignore files.
diff --git a/programs/Makefile b/programs/Makefile
index 9e1a527..b153407 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -60,6 +60,7 @@
 	pkey/rsa_decrypt$(EXEXT)	pkey/rsa_encrypt$(EXEXT)	\
 	pkey/rsa_sign$(EXEXT)		pkey/rsa_verify$(EXEXT)		\
 	pkey/rsa_sign_pss$(EXEXT)	pkey/rsa_verify_pss$(EXEXT)	\
+	psa/crypto_examples$(EXEXT)					\
 	psa/key_ladder_demo$(EXEXT)	psa/psa_constant_names$(EXEXT)	\
 	ssl/dtls_client$(EXEXT)		ssl/dtls_server$(EXEXT)		\
 	ssl/ssl_client1$(EXEXT)		ssl/ssl_client2$(EXEXT)		\
@@ -308,6 +309,10 @@
 	echo "  CC    x509/req_app.c"
 	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) x509/req_app.c    $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
 
+psa/crypto_examples$(EXEXT): psa/crypto_examples.c $(DEP)
+	echo "  CC    psa/crypto_examples.c"
+	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) psa/crypto_examples.c    $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
+
 clean:
 ifndef WINDOWS
 	rm -f $(APPS) $(EXTRA_GENERATED)