Add config for gometalinter

Add config for gometalinter

As there are differences between Boruta and Weles (e.g. usage of
vendoring) we need different sets of linter policies.

Tool:
https://github.com/alecthomas/gometalinter

Install:
$ go get -u gopkg.in/alecthomas/gometalinter.v2

Using gometalinter in Weles repository root will use this config by
default.

Config file documentation:
https://github.com/alecthomas/gometalinter#configuration-file

Format of the config file is determined by Config struct:
https://github.com/alecthomas/gometalinter/blob/master/config.go

There is an issue with gas installation currently:
https://github.com/alecthomas/gometalinter/issues/508

Currently there is a pull request to add support for ignoring generated
files:
https://github.com/walle/lll/pull/4

In current patchset generated files are excluded manually (by pkg or
filename)

Change-Id: Ib750066370392d44555aa5b5d4f342acc06c9b36
Signed-off-by: Alexander Mazuruk <a.mazuruk@samsung.com>