Migrate non-cluster tests to their own directory

[mkcp]

Is your feature request related to a problem? Please describe.

Currently, our e2e tests rely on explicit ordering with numbered prefixes. This has some downsides where adding a new test takes implicit knowledge about how tests are numbered, and in a way understanding each other test in the batch. Let's decouple them so we can run tests more simply, and in parallel.

Describe the behavior you'd like

Let's move the e2e non cluster tests (0 - 19) and make test-e2e-without-cluster to run non-cluster tests out of a subdirectory instead. Remove each number prefix and ensure that no e2e test relies on another.

Additional context

• main_test.go still must run first.
• Tunable timeouts would be nice but not required. 35m feels arbitrary