Update timestamp and timerange types to use string patterns

[philipnbbc]

Details

This PR changes the timestamp and timerange types in the JSON schemas to use pattern rather than a descriptive-only format. This PR also fixes the X-Paging-Next-Timerange header value type and expands the timerange that can be POSTed to the /storage endpoint.

Pivotal Story

Story URL: https://www.pivotaltracker.com/story/show/186122009

Related PRs

Where appropriate. Indicate order to be merged.

Links to external test runs/working deployment

Where appropriate, if separate to default CI run

Submitter PR Checks

(tick as appropriate)

• Added bbc/rd-apmm-cloudfit team as a reviewer
• PR completes task/fixes bug
• Tests exercise code appropriately
• New features and API breaks are flagged in commit messages using magic strings
• Repo maintainer is notified that a release is required
• Documentation updated (README, Confluence, Docstrings, API spec, Engineering Guide, etc.)
• Downstream repos have been checked for potential breaks & fixed as needed
• APIs/UIs/CLIs updated as required
• PR added to Pivotal story
• Follow-up stories added to Pivotal
• Any temporary code/configuration removed (e.g. test deployment environment, temporary commontooling branch)
• Any pins against pre-releases have been removed

Reviewer PR Checks

(tick as appropriate)

• PR completes task/fixes bug
• Tests exercise code appropriately
• 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 Cloudfit PRs

• The checks above are guidelines. They don't all have to be ticked, but they should all have been considered.
• For more details on how to asses PRs, see: https://github.com/bbc/rd-apmm-docs-ways-of-working/blob/master/workflow/PRChecklist.md

[C-Lunn]

Looks good to me.