* Update to Xcode 15
## Summary
We want to make Texture build with recent tools like Xcode 15. Part of this is bumping the minimum supported OS to iOS 14.
I only removed the dead code (i.e. code gated on versions older than iOS 14). There are still some warnings about outdated APIs in use, but they are non-trivial changes to fix.
## Test plan
Run all the examples. Run all the unit tests and make them pass.
* Use Xcode 15.3 so we have 17.4 simulators
* Fixing an asset catalog compiler error when building against iPhone SE
* Fix a couple of file extensions for assets
A couple of PNGs were marked as JPGs
* Convert the codebase to Objective-C++ throughout. One language is better than two.
* Put it back
* Fix linker
* Point explicitly to updated Weaver to unblock build
* Revert "Point explicitly to updated Weaver to unblock build"
This reverts commit fdc25296e8794d4e6e56c35f5fe6da2be3f71dbc.
* Revert "Fix linker"
This reverts commit 7be25f91519b8497ef42de79f115bcfbdb965c39.
* Add in the frameworks
* no message
* Address spec lint warnings
* Fix tvos build
* Put that back
* Address Michael's review
* Add comment to kick CI
Andy Finnell
Michael Schneider
Adlai Holler