Use Docker instead of dbdeployer for local testing

[daniel-nichter]

I propose we use Docker rather than dbdeployer because Docker is industry standard, and I bet it's far more common with developers than dbdeployer. It's also pretty easy to set up multiple version with Docker Compose.

If you agree, I'll do a PR later.

[morgo]

I like dbdeployer, but I agree predicated on two assumptions:

• It doesn't increase CI time in bootstrapping the tests (it shouldn't)
• We can still get the same major/minor versions to test on. The availability of 5.7.12 is becoming more scarce, but we still need it to test Aurora 2.11.x (there have been bugs specific to this being a very old minor version. For example: Regression in master: SET transaction_isolation = 'repeatable_read'; github/gh-ost#1262 )

[morgo]

Since this issue was created, dbdeployer has reached end of life. I'm adding the help-wanted tag to this issue.