Allow the user to set his own client certificate

This will allow the user to use ArduinoBearSSL without the ECCX08 (for
example with an (e)SIM applet compliant to the new GSMA IoT SAFE standard)

Signed-off-by: Fabrice Fontaine <fabrice.fontaine@orange.com>

Author: ffontaine

src/BearSSLClient.cpp

@@ -205,6 +205,11 @@ void BearSSLClient::setEccSign(br_ecdsa_sign sign)
   _ecSign = sign;
 }
 
+void BearSSLClient::setEccCert(br_x509_certificate cert)
+{
+  _ecCert = cert;
+}
+
 void BearSSLClient::setEccSlot(int ecc508KeySlot, const byte cert[], int certLength)
 {
   // HACK: put the key slot info. in the br_ec_private_key structure

src/BearSSLClient.h

@@ -74,6 +74,8 @@ class BearSSLClient : public Client {
   void setEccVrfy(br_ecdsa_vrfy vrfy);
   void setEccSign(br_ecdsa_sign sign);
 
+  void setEccCert(br_x509_certificate cert);
+
   void setEccSlot(int ecc508KeySlot, const byte cert[], int certLength);
   void setEccSlot(int ecc508KeySlot, const char cert[]);