Snippet: add Explore API call (#303)
Snippet: add Explore API call (#303)

* Snippet: add Explore API call

See https://docs.gitlab.com/ce/api/snippets.html#explore-all-public-snippets

* Snippet: add missing raw_url property

* Some renames for consistency

mickymiek/go-gitlab,xanzy/go-gitlab,nyxi/go-gitlab