Add postgres support

[liquorvicar]

Add support for installing the Postgres integration.

Possible Solution

I've created a PR for this: #98

Additional context

The PR is showing that I haven't signed the CLA but I've checked a few times and I have definitely signed it.

[yvann-ponce]

This postgres support would be appreciated thanks

[liquorvicar]

Apologies I got my GH accounts mixed up, which is why the CLA wasn't showing as signed on the PR. I have fixed this now. What else do we need to do to get this merged? cc @pranav-new-relic (as you're the last person I can see committing to main in the repo).