Compare attribution to any other attribution/signal

[alexzurbonsen]

Is your feature request related to a problem? Please describe.
It can be helpful to compare attributions to signals to figure out what changes were made.
Currently, that is possible to a certain extent by using the newly introduced "compare to original" popup (see #2488) which opens a popup in which the selected attribution is compared to its original signal. This is only possible if there is an original signal.

Describe the solution you'd like
Extend the functionality of the Diff Popup to compare an attribution to a source signal or attribution chosen by the user.
Instead of opening a popup, this could be integrated into the audit view which should dynamically change if comparison / diff view is activated.

Further changes to the current diff popup functionality that should be considered:

• make the attribution side editable
• show the revert arrows on the side of the signal or attribution that the current attribution is compared to (like in the diff view of IDEs)
• no need for redo errors anymore and an internal buffer state of the popup anymore, as all revert actions would modify the temporaryDisplayPackageInfo of the attribution directly (user should use the revert button from audit view to undo changes instead)
• include auditing options in the comparison as well. This should be a natural consequence of showing the comparison in audit view directly. As the current attribution remains editable, the auditing options do as well and need no separate revert functionality