* Setup NativeUIRequests as an AZ::Interface. Adds a NativeUISystemComponent to AzFramework Application.
* Renames NativeUISystemComponent (class) to NativeUISystem, since it's no longer a Component.
* Minor update to SettingsRegistryInterface::Remove doc-comments for accuracy.
* Fixes to make an early fatal shutdown of Editor occur without crash.
* LYN-2723: Updates startup to handle errors: engine root is empty, no valid project.json found (mismatched engine name), or bad project path (launch project picker dialog).
* LYN-2723: Minor formatting/spelling edits.
* LYN-2723: Moves ParseCommandLine from ComponentApplication to SettingsRegistryMergeUtils so it can be used in more places.
* Misc fixes. 'wait_for_connect' setting wasn't being properly applied to AP connection settings. Fix infinite loop in CCmdLine::Next.
* LYN-2723: Addresses review feedback.
* LYN-2723: Reverts some changes that caused a unit test to fail.
* LYN-2723: Reverts one more change that was unnecessary.
Eric Phister
alexpete