Support for EC curve P-384

[romanstrobl]

Description

Add implementation of ECDH and ECDSA with curve P-384:

• ECDSA, use SHA3-384 to calculate data hash and P-384 to sign or verify the signature
• ECDH, use P-384 to establish shared secret

Review existing code where P-256 curve is used and refactor existing code where necessary.

Cover the new EC curve algorithm implementations by tests.

Acceptance criteria

Implemented ECDH and ECDSA on curve P-384. Functionality is covered by unit tests.

Technical specification

https://csrc.nist.gov/pubs/sp/800/186/final
https://csrc.nist.gov/pubs/fips/186-5/final

QA specification

Functionality is tested by unit tests.