Issue #3388784 by pfrenssen: Alert developers if the config split folder is not correctly configured

Issue #3295853 by bircher, mstrelan: Split config removes settings and third_party_settings, leads to fatal TypeError

Issue #3263968 by bircher: separate state config override services to attempt to avoid circular references in some cases

Issue #3279331 by bircher, jollysolutions, pyrello: Allow customising the way sequence keys are generated

Issue #3276681 by prudloff, bircher: Patch is lost if the same config is not a patch in another collection

Issue #3238855 by bircher, pyrello, neclimdul, sker101, mparker17: Better patch creation with addressable keys

This reverts commit da4bcf63.

Issue #3246696 by bircher, pyrello: Allow comparing the partial config with the sync storage and all other active splits