End to end test - e2e, k6, system

[titpetric]

The /system/routes_test.go file is failing suspiciously failing. We already discussed looking at K6 to provide an external e2e service. Update the test and run the service externally:

• start http server in go test (for coverage),
• run k6 tests,
• shutdown test server (via HTTP request?)

[titpetric]

@darh I'm gonna assign you since this tests deal with /auth/login and such (user self service without OIDC).