Add option to reset attribution content to content of original signal

[FlorianSchepers]

Is your feature request related to a problem? Please describe.

• In case an attribution is generated from a signal, modified and the changes are saved, there is no streight forward way to figure out which changes have been made to the attribution in hindsight.

Describe the solution you'd like
Enable the user to revert all changes made to the attribution from the point when it was initially generated from the signal

Implementation

• Change the the Revert button into a drop down menue with the two options: Revert latest changes and Revert to original values (??).
  

• When selecting Revert latest changes it behaves like the current Revert button and just reverts all unsaved changes.

• When selecting Revert to original values it resets all fields of the attribution to the values of the signal linked via the origin id.

• In case an attribution has no origin id the option Revert to original values is dissabled.

Additional points

• Make sure that for attributions with the chip modified previously preffered the chip is changed back to previously preffered (i.e. the state should be back to was_preferred).
• The reset button in the chip modified previously preffered is no longer required an can be removed.

Describe alternatives you've considered

• Adding a diff view that shows the values of the origianl signals additionaly to its current values in the fields of the attribution. We decided against this option as it would cause a bad ux when the content of the fields becomes to large.

Additional context
This Issue is a follow up from #2401

[mstykow]

Done in #2488