[Feature Request]: Use custom stringified worker

[mydea]

Preflight Checklist

• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

What package is this feature request for?

rrweb

Problem Description

I noticed that for canvas recording, an base64 encoded inlined web worker is used. This is quite large in bundle size.

Proposed Solution

We could rewrite this to build a stringified web worker ourselves, like done in this PR: getsentry#144

If this sounds good to the core maintainers, I would port this PR over here as well?

Alternatives Considered

Keep it as base64 encoded (=larger, but a bit simpler setup)

Additional Information

We've been using such a stringified web worker in the Sentry SDK successfully for some time now.