allow overriding more config settings via env vars

What does this PR do?

Add a few bits of config that I had forgotten the first time around.

id in particular is necessary if one wants to do a working basic configuration without a config file at all, thanks to @4censord for making me notice

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requested review from @Leah, @fEmber, @tess, @Marie, and @luna

approved this merge request

Is it possible to allow all properties to be overridden?

added 1 commit

• 955fda6e - also allow `db.disableCache`

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approved this merge request

mentioned in merge request !584 (merged)

approved this merge request

resolved all threads

merged

mentioned in commit 265afa90