Migrate to ESM

[CMCDragonkai]

Specification

This should be migrated to ESM, all upstream libraries is already ESM.

Also while doing this, we should conditionally import perf_hooks. Because browser environments would rely on the global performance API instead. And one of the whole points was to use top level awaits as way to switch between browser implementation or node implementation.

Additional context

• Migrate to ESM (and get dynamic await) TypeScript-Demo-Lib#32
• Migrate to ESM (and get dynamic await) TypeScript-Demo-Lib#32 (comment) - make sure to address this

Tasks

1. Collate migration style from all repos
2. Migrate this repo
3. Release v2.0.0

[linear]

ENG-506 Migrate to ESM