Multiversion package support

[nelsonkopliku]

This PR follows up discussion trento-project/wanda#150 and adds support for multiversion package detection.

Gatherer now returns a list representing the installed versions for the specific package

Only one version installed detected

$ trento-agent facts gather --gatherer package_version --argument sbd
...
[
  #{
    "version": "1.5.1+20221128.8ec8e01"
  }
]

Many versions installed detected for the package (sbd in the example)
As agreed, versions are ordered by installation time desc - latest installed first.

$ trento-agent facts gather --gatherer package_version --argument sbd
...
[
  #{
    "version": "1.5.1+20221128.8ec8e01"
  },
  #{
    "version": "1.5.1+20211116.6bb085f"
  }
]

With this we should be able to unlock trento-project/wanda#124 and relevant premium checks.
Doc update here trento-project/wanda#182

[arbulu89]

Hey @nelsonkopliku ,
Good job!
I find the some of the code ultra defensive, for scenarios that I don't know even know can really happen, but no harm I guess. The installedVersions[0].Version is the one that could worry me, but maybe it cannot even happen to not have any value there

PD: I would never imagine of doing this with env parsing hehe
But good call

[arbulu89]

Thanks @nelsonkopliku