Add e2e tests running test scripts

[pablochacin]

Presently, integration tests test the golang code. Additional tests are required to ensure the js extension works properly.
These tests should

1. launch a test cluster
   2 setup resources (e.g. deploy pods, expose services)
   3 execute a test script

Steps 1. and 2. can reuse existing test setup utils.

Step 3. requires a mechanism for executing a script and validate the results. Two approaches could be used here:

• Run the xk6-disruptor binary as a process passing the test script from a file. This approach makes difficult to check the result (output needs to be parsed)
• Setup a test goja environment and load a execute the script (see for example this test). This approach has the inconvenient that it is not really testing the final extension (for example, the initialization code)