Add new repository checklist

[Christdej]

Summary

Adds docs/new_repo_checklist.md — a codification of the repository settings, rulesets, environments, secrets, variables, and labels currently used across sara-, flotilla, and isar- service repos.

Intended to be followed after creating a new service repo from equinor/sara-python-template (which only ships files — GitHub template repos cannot copy repo settings).

Contents

The doc walks through 10 numbered sections, each with:

• A description of the intended state.
• A gh / gh api command to set it.
• A gh / gh api command to verify it.
• "Known drift" callouts flagging where existing repos deviate from the convention (based on a survey of the current sara-* repos).

Sections:

1. Repository settings (merge methods, delete-branch-on-merge)
2. Branch ruleset on main
3. Required status checks
4. GitHub Environments
5. Actions secrets
6. Actions variables
7. Labels
8. Dependabot
9. CODEOWNERS
10. Register in infrastructure

Plus a "Compliance check for existing repos" section at the end — one gh api snippet you can run against any repo to eyeball its current state.

Motivation

sara-python-template handles the file scaffolding for new services, but templates can't copy settings, environments, secrets, or rulesets. Today those are set per-repo, with drift:

• Some sara repos have a branch ruleset called main, some default, two have none.
• Required approving reviews vary (0 in sara-anonymizer, 1 in sara-rain-drop-detector).
• Only sara-anonymizer has any GitHub Environments configured.
• Several sara repos still hold obsolete ROBOTICS_AURORA* secrets from before the registry consolidation.

The doc gives contributors a single, reviewable source for "what does a properly-configured sara service repo look like" — without requiring org-admin access to set up rulesets at the org level.

Follow-ups (out of scope)

• Promoting the ruleset from a per-repo pattern to an org-level ruleset targeting sara-* / isar-* / flotilla would remove the drift problem entirely. Requires org-admin access.
• Retroactively applying the checklist to bring existing repos into compliance.