One shot sign/verification ECDSA (#3029)

* Add sign and verify methods to ECDSA

* Documented ECDSA sign/verify methods

* Added CHANGELOG entry

* Skipping test verify and sign if curve is not supported

* Fixed typo in documentation return type

* Removed provider language from EllipticCurvePrivateKey and EllipticCurvePublicKey
6 files changed