Add immudb driver

[ldej]

Initial draft of immudb support

[sleepycat]

Is there still interest in adding this?
It's a great contribution, and Immudb just keeps getting better.
It'd be great to see this dusted off and merged.

[MartinezAvellan]

I already use golang-migrate in my project with PostgreSQL, and now I've added Immudb.
I came to see if there was already a driver and found this branch that has been open for so long. Do you have any idea if a merge will happen?"

[ldej]

Thanks for your interest! I have not touched this code since creating the PR. I have also not used this code in any public or private projects. That being said, feel free to make a checkout and run the tests to confirm it still works.

At the time it looked like the golang-migrate project went stale. There are countless open issues and pull-requests without any responses, which demotivated me to pursue getting this PR merged.