Basic support for overlay databases #3880

Job	Run time
Diagnostic export (ubuntu-latest, nightly-latest)	1m 11s
Diagnostic export (macos-latest, linked)	1m 28s
Diagnostic export (windows-latest, linked)	3m 7s
Diagnostic export (macos-latest, nightly-latest)	1m 26s
Diagnostic export (windows-latest, nightly-latest)	2m 52s
Diagnostic export (ubuntu-latest, linked)	1m 7s
	11m 11s

Provide feedback