Use the addHeader tool to standardize the license headers

[spolti]

The goal of this issue is to add a new step to take care of the license headers as part of the go fmt make goal to keep it consistent across all files it is present.

This new step will have:

• a standalone make goal: make add-header
• will be called as part of the make fmt

Pre requisites:

• the headers should not have tabs, only spaces.

Tool to use:

• go install github.com/google/addlicense@latest

Makefile call:

.PHONY: addheaders
addheaders:
	./scripts/addheaders.sh

[spolti]

Duplicate of #74