Add vulnerability exploiters' explanation pages

[shreyamalviya]

What does this PR do?

Fixes parts of #4213

TODO

• [x] Rewrite some parts of Zerologon
• [x] Add links to reference pages at the bottom
• [x] ~Cross-check mitigations in each plugin's manifest file with the ones in the docs~ Decide an order for SNMP. The manifest's and the documentation's suggestions are slightly different. --- UPDATE: guardicode/snmp-exploiter#1

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

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 76.97%. Comparing base (0d8a3e3) to head (a045c02). Report is 4 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #4247 +/- ## =========================================== - Coverage 77.07% 76.97% -0.11% =========================================== Files 442 430 -12 Lines 14135 13599 -536 Branches 18 18 =========================================== - Hits 10895 10468 -427 + Misses 3240 3131 -109 ```

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