* Configure MoltenVK to use a dedicated compute queue for compute[*] examples with sync barriers
* Modify descriptorindexing example for iOS and variable descriptor count limitations on MoltenVK
* Remove obsolete macOS #ifdefs no longer needed for modern MoltenVK versions
* Update iOS project to fix missing vkloader.c reference and revise example list
* Set required features and API version for VVL in debugprintf example
* Remove unnecessary Apple-specific code from descriptorindexing example
* Add Layer Settings capability to VulkanExampleBase::createInstance()
* Replace setenv() in examples with Layer Settings configuration for macOS/iOS
* Update comments in examples.h and fix missing initializer in computeraytracing example
* Update imgui overlay and example to support iOS Simulator
* Update more comments in examples.h and remove redundant initializers in deferred* examples
* Separate variable descriptor count declarations for apple and non-apple platforms
* Consolidate variable descriptor count declarations for apple vs. non-apple platforms
* Configure MoltenVK with a dedicated compute queue in VulkanExampleBase() and remove from samples
