telephone_to method

You might have heard that HTML5 added the `mailto` and `tel`. I was able to find a `mail_to` method inside of Rails, but there didn't seem to be anything for `telephone_to`.

In this PR, I took the time to provide a method to generate telephone links that will add pauses, optimize for pause separators/phone extensions, and even let you add a `skype: true` option.

See the examples above the method for what you can do with it [here](https://github.com/rails/rails/pull/17956/files#diff-26e33d6e883deb07332ac9c1922eadc0R482).
Perhaps as part of normalization, accept phone components? e.g. `{ area_code, "604", number: "4401234", ext: "123" }`