Move `@sentry/replay` code to `@sentry-internal/replay`

[mydea]

As a part of #8864, we want to move the code from the replay package to replay-internal, which we re-export (in deprecated form) from @sentry/replay.

### Tasks
- [x] Move replay code to `@sentry-internal/replay`, and re-export from there in `@sentry/replay`
- [x] Deprecate all exports from `@sentry/replay`, use `@sentry-internal/replay` in `@sentry/browser`