Fix inconsistent firewall rules

[jemrobinson]

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⤴️ Summary

• Allow graph.microsoft.com from SRE identity servers
  • Note that this was allowed by DNS and the NSG, but not by the firewall
• Replace all use of raw domain names with a PermittedDomains enum
• Replace all use of ordered_private_dns_zones() with an AzureDnsZoneNames enum
• Move time_as_string to strings so that miscellaneous.py can be dropped
• Rename time_as_string to next_occurrence, fix logic and add tests.

🌂 Related issues

Closes #1882

🔬 Tests

n/a

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
data_safe_haven/functions
__init__.py
strings.py
data_safe_haven/infrastructure/common
__init__.py
data_safe_haven/infrastructure/programs/shm
firewall.py					331
monitoring.py
networking.py					167
data_safe_haven/infrastructure/programs/sre
apt_proxy_server.py					84
data.py
dns_server.py					287
hedgedoc_server.py
monitoring.py
networking.py					1703
software_repositories.py
data_safe_haven/types
__init__.py
enums.py
tests/functions
test_strings.py
Project Total

This report was generated by python-coverage-comment-action

[JimMadge]

Looks good. I much prefer these as Enums rather than functions.

[jemrobinson]

@JimMadge @craddm Are you happy to approve this now?