Improvements to tests in CI

[TimoGlastra]

I think there's a few tweaks we can make to make the tests less heavy to run:

• Use pre-generated credential definitions, revocation registries and tails files in all tests except the tests that test that the creation is working as expected. This is taking up a lot of resources when now running tests
• Split up the heavy tests (that set up a web-server etc..) from the other tests and run these separately in the CI. This adds more parallelism, and I think can improve stability. It will also be easier to re-run the heavy tests (which are the ones always failing). A good one may be to split out .e2e.test.ts and .test.ts (and we should look if they are named correclty
• See if we can further reduce usage of resources (use in-memory wallet in more places, replace actual HTTP server with mock server, etc..)