Add secp256k1 & brainpool EC curves

[waltkb]

No description provided.

[whyoleg]

Thanks for the initiative and PR!
Are those added curves (brainpool) supported by both openssl and JDK (with BC and with default) providers?
It would be nice to add tests for them.

Additionally, you will need to run apiDump task

[waltkb]

secp256k1:

• I can confirm this works with val provider = CryptographyProvider.JDK(BouncyCastleProvider()).
• On the normal JVM provider (val provider = CryptographyProvider.JDK) this also works for me.
• I also verified that with cryptography-provider-openssl3-prebuilt it works

brainpoolP256r1:

• works with val provider = CryptographyProvider.JDK(BouncyCastleProvider())
• and also val provider = CryptographyProvider.Openssl3

[whyoleg]

Nice!
That means that we could add tests for those in:

• EcdsaTest - in both tests, probably curves could be extracted in class variable
• EcCompatibilityTest - it will affect both ECDH and ECDSA tests. Let's add all curves there and see how will it affect tests duration on CI.

secp256k1 is already tested there, so only brainpool curves should be added to tests