Use golang "vanity" URLs for imports

Instead of having golang imports for writefreely be github. com/writeas/writefreely/… you could use a “vanity” URL for imports, this also would allow you to move away from github if at one point you needed to in the future.

An example of this being done in a golang project is Gitea, we use code.gitea. io/… for our imports, and it has allowed us to migrate away from Github without needing to update any code (we just update the reference in our hugo site to the new repo location). An example repo of this being done: https://gitea.com/gitea/redirects (I also have a repo that does this for my personal projects: https://github.com/techknowlogick/go-vanity-url, note the gitea project is more robust due to not having to be aware of subpackages in imports)

(please excuse the spaces in the URLs above, as I was limited to only two URLs per post)