Update Travis automation to use current "metal-cli", avoid deprecated "facility" API

[vielmetti]

Description

(Describe the feature, bug, question, proposal that you are requesting)

On the Equinix Metal (formerly Packet) platform, it was observed that automation that
relies on our deprecated "facilities" feature was failing, resulting in Travis nodes not
being torn down at end of use.

Importance

(Indicate the importance of this issue to you (blocker, must-have, should-have, nice-to-have))

Undeleted nodes are accumulating credits, which are part of a finite CNCF credit allocation.
In addition at some extreme if machines are being turned on without ever being turned off and
sit idle for a long time it is not a sustainable situation.

Location

(Where is the piece of code, package, or document affected by this issue?)

Code identified by the search for "packet-cli" command

https://github.com/search?q=repo%3Apravega%2Fpravega-operator%20packet-cli&type=code

Suggestions for an improvement

(How do you suggest to fix or proceed with this issue?)

1. Replace old "packet-cli" code with current supported "metal-cli" https://github.com/equinix/metal-cli
2. Replace "facility" API with "metro" API https://deploy.equinix.com/developers/docs/metal/locations/facilities/
3. Explore using a different machine type / location that might have similar performance + lower cost and impact

Thanks @RaulGracia for the assistance.

[vielmetti]

The "facility" API has been turned off, and so the old automation based on the "packet-cli" code will no longer work; you should get a 422 error.

Let me know if you want to schedule a time to review; I am available.