Add support for Google CDN

This commit adds base support for using Google CDN in front of an
object storage bucket to save costs. Note that this commit does not
actually enable the use of the CDN yet; additional configuration and
changes to the callers must be made for this to work.

To enable a bucket to use the Google CDN:

1. A CarrierWave uploader should `include ObjectStorage::CDN::Concern`.
2. Instead of calling `#url`, a caller can now call `#use_cdn?` and
   `#cdn_signed_url`.

At the moment, transfers within the Google Cloud Platform (GCP)
network between Google Cloud Storage and virutal machines are free, so
serving out artifacts to GCP machines would waste money in the form of
egress traffic.

To avoid that, `#use_cdn?` will fetch the list of valid, public Google
IP ranges and exclude IPs that are private or within the public Google
network.

`#cdn_signed_url` will create a pre-signed URL valid for 10 minutes by
default. The Google CDN must be set up so that a Google Cloud
Storage bucket is behind a unique URL.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/360462

Changelog: added