At least from 1000 feet away, it seems like Ruby has this problem solved better than Go does. Maybe it's just that the nature of the solution is more apparent.
Anywhere you want to publish them.
>Can I install things from this page[1] in that way?
Sure. Just do a "go install github.com/foo/bar". Bitbucket, github, google code, and launchpad are all in the defaults, but you can configure your import path to add whatever locations you like, and then "go list" will show packages available there, and the other go commands will be able to build/install/etc those. The same syntax is used for import statements, so your code can depend on any code any where:
import "mycoolwebsite.com/~bob/myproject.git/foo"
I think they make it pretty clear: http://golang.org/cmd/go/ gives you pretty much everything about packages and so does "go help". Go pretty much does everything out of the box with the included toolset, from installing dependencies to formatting code to refactoring.
Now replace go with ruby and ruby with perl. Go has libraries for 99% of what people are doing with ruby. If you are in that 1%, then you need to evaluate whether or not it is worth writing the library you need or if you should use another language.