* Refactor user's device assignment logic

* Extract device assignment logic into app methods

* Move device retrieval into control flow

* Move un\assign logic into control flow

* Extract mobile callflow update into own function

* Patch device owner_id instead of full update

* Move mobile callflow id retrieval to control flow

* Patch callflow to avoid having to retrieve it first

* Consolidate un\assignment logic

* Migrate single-used app methods into closure

* Extract mobile callflow update logic into app method

* Run device patch and mobile callflow update in parallel

* Move back device assignment logic to users module

* Consolidate mobile callflow update w/ user callfow fetching logic

* Update linked callflow on mobile device un\assignment

* Refactor entities update logic on device un\assignment