refactor: migrate to ESM

[hi-ogawa]

• merge base refactor: update to remix vite #519
• closes refactor: from cjs to esm #525

todo

• fix knex
• fix cli
• esbuild-register -> tsx
• fix __filename in playwright tests
• still needs to bundle as cjs for vercel serverless? (EDIT: fixed in e385991)
  • Not sure why esbuild can bundle @remix-run/server-runtime into ESM app (cf. chore: build ESM for vercel serverless remix-vite-deployment-examples#8), but mysql2 seems to have some problem. Is this only for node dependency e.g. "process", "net"?
  • relevant issues and workaround found from https://github.com/evanw/esbuild/issues?q=is%3Aissue+is%3Aopen+__require
    • How to fix "Dynamic require of "os" is not supported" evanw/esbuild#1921 (comment)
    • Rewrite require() calls of Node built-ins to import statements when emitting ESM for Node evanw/esbuild#2067 (comment)
  • maybe it's time to try vercel's ncc? https://github.com/vercel/ncc

[hi-ogawa]

Manually deployed since CI seems to have some issues:

• Vercel deploy error on CI? #539