Enable Destination Acceptance Tests cross-language support

Subtasks:

- [x] Create a runner which launches DAT in a Docker image with external configuration
- [x] define external configuration model and how user can configure it
- [ ] Create python superclass to implement necessary DAT methods
- [ ] Implement DAT for KVDB
- [ ] Create boilerplate Dockerfile for running Python subclass implementation
- [ ] Create a shell runner script to run DAT from non-java connectors (similar to `acceptance-test-docker.sh` for SAT)
- [ ] Edit python destination template to use new DAT by default
- [ ] Save breadcrumbs to tmp location for debugging
- [ ] Autogenerate reference docs for the test cases + input user configuration