Convert to range-based for loops (#5417)

* Changed iterators to range-based for loops in apps

* Reverted construct

* Reverted another pseudo-container

* Removed constness

* Reverted a file I can't build/test locally

* Fixed a typo

* Applied another fix

* Modernized loop properly

* Fixed clang-format complaint

* Converted more for-loops to range based

* Fixed typo

* FIxed missed changes

* Changed (some) manual for loops to range-based

* Fixed clang-format escapes

* Rebased on upstream, fixed compile issues

* Reverted indexed loop conversions per review

* Made corrections per review