Github workflow to create an Endo bundle for publishing to the chain

[turadg]

What

Add a triggerable Github Action that builds a CoreEval and its bundles.

Why

We've sometimes built them on laptops and there is variation between environments. We should have a clear provenance with a public record of how the code was built.

How

[incomplete, needs design

• Add a new Github action that is only triggered.
• It takes a package name and a script target (e.g. portfolio-deploy, deploy-devnet)
• It gets the same JS environment as the test jobs
• It runs the command in that environment, capturing all logs and the build artifacts
• It outputs in the job log what to do next (take the artifacts to https://cosgov.org/, etc)