Switch to testcontainers-go

[mfridman]

Picking up an action item from #520

Addes testcontainers-go and google-cmp as dependencies for end to end tests. Testcontainers offers much better API for providing disk mounts and ensuring cleanup.

I've also started to use this project in favor of https://github.com/ory/dockertest. This issue aims to capture some of the work to get goose ported over.