Add vendor license checks to PR (#744)

* Add vendor license checks to PR

This PR aims to add automatic detection of licenses of vendor-ed packages for every PR raised
to the Odo repository using a tool called [wwhrd](https://github.com/frapposelli/wwhrd) that
iterates on every vendored package, searches for the license file, detects the license type
and validates the detected license type against the different sections of the configuration
file .wwhrd.yml.

fixes #743
Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

* Incoporate comments from @surajnarwade

Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

* Incoporate @tkral Comments

Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

* Add documentation about the license checks

Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

* Incoporate @codeclimate comments

Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

* Incoporate @cdrage comments

Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

* Incoporate @cdrage and @kadel comments

Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

* Incorporate @cdrage comments

Signed-off-by: anmolbabu <anmolbudugutta@gmail.com>

.wwhrd.yml

@@ -0,0 +1,17 @@
+---
+blacklist:
+  # https://www.apache.org/licenses/GPL-compatibility.html
+  - GPL-2.0
+
+whitelist:
+  - Apache-2.0
+  - MIT
+  - NewBSD
+  - FreeBSD
+  - ISC
+
+exceptions:
+  # wwhrd currently does not detect ISC which is compatible with Odo so, add it under exceptions to avoid errors due to it being not recognised
+  - github.com/davecgh/go-spew/spew/...
+  # wwhrd currently does not detect ISC which is compatible with Odo so, add it under exceptions to avoid errors due to it being not recognised
+  - github.com/olekukonko/tablewriter