3392 gzip plugins

[ilija-lazoroski]

What does this PR do?

Fixes #3392 .

Add any further explanations here.

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?
• Have you checked that you haven't introduced any duplicate code?

Testing Checklist

• Added relevant unit tests?
• Do all unit tests pass?
• Do all end-to-end tests pass?
• Any other testing performed?

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

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

[mssalvatore]

It looks like the agent changes got dropped. The Island should be recompressing source archives before sending them to the agent to save network traffic and to keep the AgentPlugin types consistent.

[mssalvatore]

Approved. Waiting on MSI tests.