feat(hasura): metadata v3 support

[WonderPanda]

Improvements

Adds support for the new metadata v3 format

Todo Before Merge

• Add tests for v2 metadata to ensure we don't break things for existing users
• Add tests for cron events

[WonderPanda]

@BraunreutherA If you feel like having a look

[BraunreutherA]

@WonderPanda thanks for your work on this. Very well implemented!

[BraunreutherA]

Is there a reason why the test fixtures are in the .gitignore? I think then we would have to generate them on every test run.

[WonderPanda]

Is there a reason why the test fixtures are in the .gitignore? I think then we would have to generate them on every test run.

@BraunreutherA If they are not added to .gitignore then they will generate changes to the repo everytime someone runs the tests. I feel like it would be confusing for people pulling down the codebase if they have a fresh copy of the repo and then run tests and see a whole bunch of changes in git.

I've updated the logic to properly copy over the .tmpl files at test startup