Adds back company switcher to the app for people with more than one company.
Appears in the header on all the pages.
Feature [#39518117] Re-add company switcher
Added the feature back to the app, but just like the year filter, it
needs to be DRY'd up before the merge happens.
Moved company switcher to general layout template to avoid duplication.
Removes unneeded modification to company decorator.