ui: Rework editing of permissions

[mathiashoeld]

Current situation

When editing permissions, each click performs an API action and grants/revokes permissions. This is not ideal for some reasons:

• If an error was made, it is written permanently to the chain
• The scenario where a user grants permissions, but cannot revoke them is possible - which combined with the first issue can cause problems
• There is no way to restore the original state during edit (i.e. no "cancel" button)

Proposed solution

Similar to the drawer in the batch edit function for workflowitems, the permissions should be changed in the permissions window without any action on API level and only after click of "apply" the changes are persisted to the chain.
Additionally, add a "cancel" button that simply cancels the process and takes the user back to the previous screen.
This should be done for global permissions as well as permissions for projects/subprojects/workflowitems.