Modify SSH exploit

[ilija-lazoroski]

What does this PR do?

Modify SSH exploiter, related to #1605.

PR Checklist

• Have you added an explanation of what your changes do and why you'd like to include them?
• Is the TravisCI build passing?
• Was the CHANGELOG.md updated to reflect the changes?
• Was the documentation framework updated to reflect the changes?

Testing Checklist

• Added relevant unit tests?
• Have you successfully tested your changes locally? Elaborate:

  Tested by {Running the Monkey locally with relevant config/running Island/...}

• If applicable, add screenshots or log transcripts of the feature working

[shreyamalviya]

We should also get rid of any stale code in HostExploiter now.

[shreyamalviya]

Instead of creating a dictionary exploit_result and passing everything to ExploiterResultData one by one, we could use default values for named tuples, and simply instantiate it as self.exploit_result = ExploiterResultData() in pre_exploit(). Then, we could simply modify that object instead of having a dictionary tracking the exact same values.

[mssalvatore]

Instead of creating a dictionary exploit_result and passing everything to ExploiterResultData one by one, we could use default values for named tuples, and simply instantiate it as self.exploit_result = ExploiterResultData() in pre_exploit(). Then, we could simply modify that object instead of having a dictionary tracking the exact same values.

@shreyamalviya NamedTuples are immutable. We could convert it to a dataclass. The conversion will happen sooner or later, I don't much mind if it happens here or down the road.

[shreyamalviya]

@mssalvatore I'll do it now so we won't have to modify the exploiters again.