Split `packages` folder into semantic folders

[mydea]

Currently, we have all our monorepo packages in a single packages folder. While this works, the list of packages is becoming longer and longer.

I propose to split the single packages folder into multiple folders like this:

# Public packages (@sentry namespace)
- packages 
  - angular
  - browser
  - core
  - ember
  - gatsby
  - hub
  - integrations
  - nextjs
  - node
  - opentelemetry-node
  - react
  - remix
  - replay
  - serverless
  - svelte
  - tracing
  - types
  - utils
  - vue
  - wasm
# Internal packages that are still published (under @sentry-internal namespace)
- packages-internal
  - eslint-config-sdk
  - eslint-plugin-sdk
  - typescript
# Fully private packages that are not published
- packages-private
  - e2e-tests
  - integration-tests
  - node-integration-tests