feat(cedarling): add property to allow specify yaml policy store file

We need to extend `CEDARLING_POLICY_STORE_LOCAL` functionality. it should support both JSON/YAML policy store formats.
Alternative solution is to add new property for YAML similar to `CEDARLING_POLICY_STORE_LOCAL` which we uses for JSON

Start by locating the CEDARLING_POLICY_STORE_LOCAL configuration and the Cedarling policy-store loading entry point. Check how JSON policy stores are selected and identify the existing YAML-related path, if any. Done means Cedarling supports YAML as well as JSON through the agreed configuration approach, with behavior verified for both formats.

Written by the indexing model from the issue text.