Add support for Elliptic Curves keys (secp256k1 and Curve25519) and signing algorithms (ECDSA and EdDSA)

[iamtxena]

eIDAS Bridge should support the following keys:

• RSA 2048 (already supported)
• RSA 4096 (already supported)
• Elliptic Curve secp256k1
• Elliptic Curve Curve25519

And the following signing algorithms:

• RSA signature with PKCS#1 padding (already supported)
• RSA signature with PSS padding (already supported)
• ECDSA
• Ed25519: Edwards-curve Digital Signature Algorithm (EdDSA) using the Curve25519