feat: introduce method to fetch origin config

This PR is a part of https://github.com/kubeshop/monokle-cli/issues/23. It introduces a method to fetch origin config (from origin/config.js file) which can be used by integrations when origin is passed.

Since this will be default approach now as we try to avoid hardcoding URLs I also deprecated default creators and added factory methods based on origin - so that integration can pass origin URL and expect to get instances with all valid config needed fetched from origin.

I planned to have it simple as just providing method to fetch origin config, but it seems all integrations would need to duplicate this logic so I abstracted it in creators.

Changes

As above.
Also smuggled minor change, to expose default config paths so StorageHandler can be reused more easily - https://github.com/kubeshop/monokle-core/pull/567/commits/107f9b1458e05ecf516aabe098c672a1040e4633.

Fixes

None.

Checklist

[x] tested locally
[ ] added new dependencies
[ ] updated the docs
[x] added a test

kubeshop / monokle-core