Enable 'undo customization' of managed (third party) solution components

[EJvdBosch]

Create a 'Undo customization' button for managed solution components.

Once a managed component from a third party solution is customized, this (unmanaged) customization will always be effective, even if the managed solution is updated.

Though this is intended behavior, there is no way to undo these customizations. This means that any update of a managed solution will not be effective. The only way to get the solution update effective, is to import the solution with 'overwrite customizations' applied. This method has to major disadvantages: 1. this applies to the whole solution, which is in most cases not desired, 2. this is a one-time solution, as this will be needed for any future solution update.

[aorth]

Adding @EvanChakiMSFT for this suggestion.

[caburk]

This is a known gap and the solution infra team is currently designing features to address it. I've sent them an email in case they can share additional information. 

As a first step we shipped an (yet to be documented) API that allows you to query layers for a given component. This doesn't solve the issue, but can provide more predictability in the interim.