Add ADR folder structure, templates and initial ADR doc

[robwadge]

Details

Add folder structure to support use of Architectural (Any) Decision Records
Add MADR template and apply slight modifications to simplify for our use
Create an initial ADR doc from the template to document the decision to use (M)ADRs

Pivotal Story

Story URL: https://www.pivotaltracker.com/story/show/186644493

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