Add logging to e2e tests

[pablochacin]

Presently the e2e tests run mostly silently. In case of failure, there's little if any indication of what went wrong.

Even with the changes recently introduced in #233 and #236 intended to improve the ability of contributors to debug failures found in the e2e tests, it is not clear for the developers for example what namespace was used by the failed test.

Therefore it would be convenient to add logs to the execution of e2e that offers hints about:

• Namespace used for the failing test
• Indications of how to reproduce the failed test and preserve resources (including the cluster) for further analysis
• Links to relevant documentation