Add ADR for a query option to filter get_urls

[philipnbbc]

Details

This PR adds an ADR that proposes a accept_get_urls query option to filter flow segment get_urls. This allows clients to indicate that pre-signed URLs are not required, potentially significantly reducing the request time when requesting a large number of flow segments.

Pivotal Story (if relevant)

Story URL: https://www.pivotaltracker.com/story/show/187930100

Related PRs

Where appropriate. Indicate order to be merged.

Submitter PR Checks

(tick as appropriate)

• PR completes task/fixes bug
• API version has been incremented if necessary
• ADR status has been updated, and ADR implementation has been recorded
• Documentation updated (README, etc.)
• PR added to Pivotal story (if relevant)
• Follow-up stories added to Pivotal

Reviewer PR Checks

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• PR completes task/fixes bug
• Design makes sense, and fits with our current code base
• Code is easy to follow
• PR size is sensible
• Commit history is sensible and tidy

Info on PRs

The checks above are guidelines. They don't all have to be ticked, but they should all have been considered.

[AndrewGibb]

A suggested change and a typo.

Once changed, LGTM.

[philipnbbc]

This PR will be left open for now as further discussion is needed to understand whether it fits the requirements or not.

[j616]

Follow the Workshop where this was discussed, we should also update the App Note describing the get_url label format to add an extra .presigned element. i.e. <provider>.<region[optional]>.<availabilityZone[optional]>:<storeType>.<presigned[optional]>:<storeName> which may be used as such example-cloud-provider.eu-west-1.a:example-storage-product.presigned:example-store-name