add KEYUTIL.getJWK, fix EC P-521 concat signature value and add support for P-521 JWS JWK

• Changes from 10.5.0 to 10.5.1 (2021-Dec-01)
  • fix ECC P-521 curve issues (#528)
    • src/ecdsa-modified.js
      • asn1SigToConcatSig fix P521 issue
      • concatSigToASN1Sig fix P521 issue
    • src/jws.js
      • add ES512 support
    • src/keyutil.js
      • fix P-521 issue in getKey,getJWKFromKey,
    • tool/tool_jwt.html
      • add ES512 support
    • test/qunit-do-ecdsamod-s.html
      • add P-521 asn1SigToConcatSig tests
      • add P-521 concatSigToASN1Sig tests
    • test/qunit-do-ecdsamod.html
      • add sha512 tests
    • test/qunit-do-jws-sign.html
      • add signing and verification ES512 test
    • test/qunit-do-keyutil-ec.html
      • add P-521 key test
    • test/qunit-do-keyutil-jwk.html
      • add P-521 private key test
    • test/qunit-do-x509-key.html
      • add P-521 certificate test
  • JWK from X509 certificate (#529)
    • this PR was merged but
      • X509.getPublicKeyJWK was moved to KEYUTIL.getJWK
      • some tests in qunit-do-x509-jwk was moved to
        qunit-do-keyutil-jwk
      • readCertJWK was removed
  • src/keyutil
    • KEYUTIL.getJWK added and x5c/x5t/x5t#S256/kid member support
    • KEYUTIL.getJWKFromKey now deprecated
  • src/ecdsa-modified.js
    • missing variable definition fix (#527)
  • test/qunit-do-x509.html test error fix
  • Great appreciate for @cplussharp 's contribution.