[keycloak-dev] Splitting server-spi into server-spi and server-spi-private

I've sent a PR for splitting server-spi into server-spi and sever-spi-private. server-spi should now aim to include only what is needed to create a user storage provider. There are more in there than I'd like, but it would be to much work to refactor things at this point. The PR is: https://github.com/keycloak/keycloak/pull/3489 I'll give everyone a chance to take a look and object to this before merging. So please review it asap as I'll be merging it tomorrow.