Rename NativeCodeAsset->CodeAsset and merge {CodeAsset,DataAsset} and {CodeAsset,DataAsset}Impl #901

Job	Run time
build (ubuntu, stable, native_assets_builder, false)	5m 0s
build (ubuntu, stable, native_assets_cli, false)	1m 42s
build (ubuntu, stable, native_toolchain_c, false)	1m 56s
build (ubuntu, dev, native_assets_builder, false)	5m 25s
build (ubuntu, dev, native_assets_cli, false)	2m 35s
build (ubuntu, dev, native_toolchain_c, false)	2m 7s
build (macos, stable, native_assets_builder, false)	7m 3s
build (macos, stable, native_assets_cli, false)	2m 32s
build (macos, stable, native_toolchain_c, false)	2m 29s
build (macos, dev, native_assets_builder, false)	5m 19s
build (macos, dev, native_assets_cli, false)	3m 11s
build (macos, dev, native_toolchain_c, false)	2m 48s
build (windows, stable, native_assets_builder, false)	7m 12s
build (windows, stable, native_assets_cli, false)	2m 57s
build (windows, stable, native_toolchain_c, false)	4m 29s
build (windows, dev, native_assets_builder, false)	7m 21s
build (windows, dev, native_assets_cli, false)	2m 58s
build (windows, dev, native_toolchain_c, false)	4m 13s
coverage-finished	5s
	1h 11m 22s

Provide feedback