Do Not Merge: pro system certified command test implementation

[renanrodrigo]

Why is this needed?

This is the diff with the code that was built and uploaded to https://launchpad.net/~ua-client/+archive/ubuntu/pro-hw-cert as part of SC-1665.

This diff implements an entrypoint in the Pro Client to verify if your system is Ubuntu Certified.

Please note:

• This is a stunt implementation, a toy version to test out how the UX will look like when running the command.
• Note I say stunt and not stub implementation for two reasons
  • to look cooler and funnier
  • because it actually implements some integration with the actual hwlib dependency so this is not purely a mock.
• The code has comments describing some expectation on how some things will improve in the future. Those expectations need to be fulfilled in the certifications side for us to be really happy.
• There are no unit or integration tests - those will be added when this actually becomes more real
• There are some simplifications in the implementations (like messages should actually go to the messages module, and proper exceptions need to be defined and raised) - forgive me, for I have sinned. I mean, this will be properly fixed when this becomes more real.

This will become more real when hwlib is ready (or at least readier) to land in the archive, with a well defined plan in mind about availability in different releases. Until then, iterations will be code-documented in this PR and published directly to our test-stage PPA.

Test Steps

Install the package from the PPA and run the pro system certified command.

• On X, B, F you will get an error because this was intended to work from J
• On J and N you will get an error when trying to install the package, as the hwlib implementation was done only for mantic at the time of this writing. Of course if the package appears on J, N in the future, this will change.
• On M you will be able to test the whole flow. Try running it as non-root vs root, and responding no, then yes to the questions in the flow. This should match the previously specified flowchart in US098.

Checklist

• I have updated or added any unit tests accordingly
• I have updated or added any integration tests accordingly
• Changes here need to be documented, and this was done in:

Does this PR require extra reviews?

• Yes - in the future we will know better
• No