Update to Kotlin 1.6.0 and associated library changes (including fixes for some deprecations)

[NaCl5alt]

Description

Upgrade Kotlin from 1.5.10 to 1.6.0 and upgrading Gradle, Compile SDK and libraries along with it.
Also, removed arm64 setting from EXCLUDED_ARCHS in xcodeproj so that it can be built on M1 Mac.
Also fixed some deprecations.

Developed system environment info

Build #AI-212.5457.46.2112.8094850, built on January 20, 2022
Runtime version: 11.0.12+0-b1504.28-7817840 aarch64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
macOS 11.6
GC: G1 Young Generation, G1 Old Generation
Memory: 1280M
Cores: 8
Registry: external.system.auto.import.disabled=true
Non-Bundled Plugins: IdeaVIM (1.9.2), org.moe.community (1.4.10), com.jetbrains.kmm (0.3.0(212-1.6.0-release-795-IJ)-132), Dart (212.5632), io.flutter (63.3.3)