[WIP] Feature/licenses check

Why not use LicenseFinder as we do with CE?

mentioned in issue #1608

Hmm... I first searched for some tool for license checking in GO applications, then found the #1608 issue and the remembered about LicenseFinder

But I see two advantages of using this instead of LicenseFinder:

LicenseFinder is a ruby tool. It needs ruby in test environment. Why to add ruby (and all needed dependencies) when we can use a "native go" tool which has the environment ready
I see that LicenseFinder supports:
- Godep
- Go workspace (via a .envrc file)
- Go submodules
while I'm thinking about migrating from Godep to Glide. I don't know if LicenseFinder will work with dependencies managed by Glide.

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@tmaczukin I used govendor in my go playgrounds.

It uses the go 1.5+ vendor folder and works pretty well. How it looks like its also supported by licensefinder

Milestone changed to %Backlog

Personally I'd recommend License Finder to keep parity with our other projects, but that's just my opinion :P

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What does this MR do?