Basic support for overlay databases #3877

Job	Run time
Diagnostic export (macos-latest, linked)	1m 11s
Diagnostic export (ubuntu-latest, linked)	58s
Diagnostic export (ubuntu-latest, nightly-latest)	1m 1s
Diagnostic export (windows-latest, linked)	5m 10s
Diagnostic export (macos-latest, nightly-latest)	1m 16s
Diagnostic export (windows-latest, nightly-latest)	2m 36s
	12m 12s

Provide feedback