Add support for scram-sha-256 authentication

[snsinfu]

This PR adds a support for scram-sha-256 authentication.

[snsinfu]

The checks seem to have failed due to a network error, but on my computer docker-compose up runs fine.

[Soremwar]

I tried it locally in my machine and it didn't work either. This is I suspect a problem on how the Docker testing structure is currently executed. I'm gonna try and fix this upstream to make the tests pass

[Soremwar]

I had to create a whole new container for scram authentication, since enabling scram would sadly disable authentication for both md5 and clear passwords

[Soremwar]

This is an incredible contribution @snsinfu
I have no further comments, though I will probably iterate over this in order to trim down some of the SHA utilities and replace them with the Deno builtin crypto that is likely to land in a couple weeks. Also I'd like to check if this works with SSL (I understand it's a slightly different protocol)