Resolve PR review comments
1) use `pk_get_rsapubkey` instead of reimplementing the parsing
2) rename the key files, according to their type and key size
3) comment in the data_files/Makefile hoe the keys were generated
4) Fix issue of failure parsing pkcs#1 DER format parsing, missed in previous commit
diff --git a/tests/suites/test_suite_pkparse.data b/tests/suites/test_suite_pkparse.data
index f34fc3c..b0464e5 100644
--- a/tests/suites/test_suite_pkparse.data
+++ b/tests/suites/test_suite_pkparse.data
@@ -108,15 +108,15 @@
Parse Public RSA Key #1 (PKCS#8 wrapped, DER)
depends_on:MBEDTLS_MD5_C:MBEDTLS_PEM_PARSE_C
-pk_parse_public_keyfile_rsa:"data_files/format_gen_der.pub":0
+pk_parse_public_keyfile_rsa:"data_files/rsa_pkcs8_1024_public.der":0
Parse Public RSA Key #3 (PKCS#1 wrapped)
depends_on:MBEDTLS_RSA_C:MBEDTLS_PEM_PARSE_C
-pk_parse_public_keyfile_rsa:"data_files/public_rsa_key.pem":0
+pk_parse_public_keyfile_rsa:"data_files/rsa_pkcs1_2048_public.pem":0
Parse Public RSA Key #4 (PKCS#1 wrapped, DER)
depends_on:MBEDTLS_RSA_C:MBEDTLS_PEM_PARSE_C
-pk_parse_public_keyfile_rsa:"data_files/public_rsa_key.der":0
+pk_parse_public_keyfile_rsa:"data_files/rsa_pkcs1_2048_public.der":0
Parse Public EC Key #1 (RFC 5480, DER)
depends_on:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP192R1_ENABLED