Golang built-in project template

Proposal

Following the Adding a new built-in project template documentation I've successfully created a template for Golang.

Working example template can be found here - https://gitlab.com/faleksic_ultimate_group/golang-example

Being a private group it might require an invitation depending on the user. I've sent an invite to @jpcyiza for review.

Per the documentation, mentioning @seancarroll and @tlinz for visibility.