Move log analytics to SRE

[jemrobinson]

:white_check_mark: Checklist

• [x] I have searched open and closed issues for duplicates.
• [x] This is a request for a new feature in the Data Safe Haven or an upgrade to an existing feature.
• [x] The feature is still missing in the latest version.
• [x] I have read through the documentation.
• [x] This isn't an open-ended question (open a discussion if it is).

:strawberry: Suggested change

We do not need a central log analytics workspace so this could be moved to the SRE

:steam_locomotive: How could this be done?

[JimMadge]

This enables #1900

Should also consider whether we want to keep/replace log analytics.