Move scripts/test-* into tests folder.

[dereknola]

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

The docker tests that run in drone have long been under the scripts directory. This is because they were originally the only tests that existed for K3s.

Describe the solution you'd like

For readability, we need to consolidate these bash scripts under tests/docker and update the TESTING.md with information on them.

Describe alternatives you've considered

Additional context