RFE: enable sorting by state in process instance view

[nitram509]

Motivation / Use Case

In order to speed up the finding/search of active instances, it would be helpful to sort by state.

Feature description

• in the process view, the table of the instances contains a sort button next to the column "state"
  • the sort button switches the sort order for the 'state' column (similar as now implemented for time)
• Optional: sorting preference of the user ist store in the local storage of the browser, for the user's convinience

@saig0 What's your view? PS: I'm willing to contribute, as usual ;)

[saig0]

@nitram509 sounds good to me :+1:

Looking forward to see your contribution :rocket: