[DX] Disabling a field should not update the weights of all fields

Description of the need

This is a developer experience improvement proposal: When disabling a field in a display mode, every field on the content type gets updated due to the field weights being re-numbered. Similarly, if you arrange the enabled fields, all fields (including disabled ones) get their weights updated. This results in unnecessary configuration file changes, which can more easily lead to merge conflicts for people managing configuration in version control.

Proposed solution

The weights for disabled fields should not be stored at all (IMO), they should default to the main field weight specified by the field configuration. Disabling a field should not modify any other fields' weight. (Though enabling a field almost certainly will modify weight, since it needs to be positioned).