Adding authenticator enrollment and verification to authentication client

[czf]

Changes

Adding support for [/mfa/associate](The authentication client doesn't support mfa/associate) to authentication client Adding support for /oauth/token verification with OOB to authentication client

Added new methods to authentication client to support the API endpoints Added request/response classes

References

resolves #694

Testing

• [x] This change adds integration test coverage

• [x] This change has been tested on the latest version of the platform/language or why not

Checklist

• [x] I have read the Auth0 general contribution guidelines

• [x] I have read the Auth0 Code of Conduct

• [x] All existing and new tests complete without errors

[frederikprijck]

Can we be consistent with naming across this PR and #698 ? E.g. #698 uses DeleteMfaAuthenticatorRequest, this PR uses AssociateNewAuthenticatorRequest, while I think AssociateMfaAuthenticatorRequest would be more consistent.

[czf]

Can we be consistent with naming across this PR and #698 ? E.g. #698 uses DeleteMfaAuthenticatorRequest, this PR uses AssociateNewAuthenticatorRequest, while I think AssociateMfaAuthenticatorRequest would be more consistent.

renamed to AssociateMfaAuthenticatorRequest

[kailash-b]

Changes are merged as part of #798