Base64 format fix

[leodido]

What type of PR is this?

/kind bug

Any specific area of the project related to this PR?

/area engine

What this PR does / why we need it:

This PR deprecates PR #988 fixing the issue with base64 format (with/without json enabled).

Which issue(s) this PR fixes:

Fixes #987

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

fix: the base64 output format (-b) now works with both json and normal output.

[leodido]

/hold

[fntlnz]

Continuation of the comments in #988 - This is the expected output with json enabled

{
  "output": "15:11:12.275341197: Notice Yo (err=G1swbRtbMDE7MzRtLhtbMG0K)",
  "priority": "Notice",
  "rule": "Test",
  "time": "2020-02-04T14:11:12.275341197Z",
  "output_fields": {
    "evt.buffer": "G1swbRtbMDE7MzRtLhtbMG0K",
    "evt.time": 1580825472275341300
  }
}

And this is with json disabled:

15:10:50.593977278: Notice Yo (err=IBtbMG0bWzAxOzM0bURlc2t0b3AbWzBtICAgG1swMTszNG1Eb2N1bWVudHMbWzBtICAgG1swMTszNG1Eb3dubG9hZHMbWzBtICAgG1swMTszNG1nbxtbMG0gICAbWzAxOzM0bVBpY3R1cmVzG1swbSAgIBtbMDE7MzRtUHJvamVjdHMbWzBtICAgG1swMTszNG1WaWRlb3MbWzBtICAbWzAxOzM0bSdWaXJ0dWFsQm94IFZNcycbWzBtCg==) 

[leodido]

/hold cancel

[fntlnz]

This was broken since 0.13.0

[poiana]

LGTM label has been added.

Git tree hash: 05aa49ffaab83b1085c57223ace9d4d70106c95a

[mstemm]

lgtm!

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fntlnz, mstemm

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