Support for downloading drive files from Google colab links

[MichaelChirico]

Here is a link to a simple Colab file in my GoogleDrive:

https://colab.research.google.com/drive/1Dcf35JDcpxXjahcSHVJtQFkBaLhhQWLu?usp=sharing

As a Colab file, it's stored in my drive & at root it' "just" a json file.

I would expect drive_download() to accept that URL, but as_id() fails for this:

as_id("https://colab.research.google.com/drive/1Dcf35JDcpxXjahcSHVJtQFkBaLhhQWLu?usp=sharing")
# <drive_id[1]>
# [1] NA

[jennybc]

I've labelled this for tidy-dev-day, but note there is a PR (#460) that will close this.

On dev day, I'd be interested in someone checking out this PR and verifying it works for them. The PR raises some questions about Drive links and points out that the regex work became more opaque. So any analysis / suggestions on those fronts would be useful! Basically PR review is what's needed.