* Encapsulate message transport by removing `ExternalReaderProcess.getTransport` and adding `getModuleResolver` and `getResourceResolver` methods
* Reuse `Random` instances within `ExternalReaderProcessImpl` and module/resource resolvers
* Externalize all `ExternalReaderProcessException` messages
* Add some missing doc comments to `ModuleKeyFactories` and `ResourceReaders` methods for external readers
* Move org.pkl.core.util.Readers to org.pkl.core.Readers
* Load `PklProject` using the same security settings and env vars passed provided via ExecutorSPIOptions
* Handle thrown `PklException` from loading `PklProject` and throw `ExecutorSPIException`
* Handle thrown `PklException` of older Pkl distributions, converting them into `ExecutorSpiException`
This adds a new feature, which allows Pkl to read resources and modules from external processes.
Follows the design laid out in SPICE-0009.
Also, this moves most of the messaging API into pkl-core
Fix a bug where overwriting `output` causes a PklBugException.
This now produces a more helpful message pointing to the actual problem.
Co-authored-by: translatenix <119817707+translatenix@users.noreply.github.com>
In messages "Read Resource Response" and "Read Module Response", if `contents` and `error` are both null, default to an empty byte array/string.
This resolves one of the issues reported in #656
