Validate named references to bindings, guards, vaults, catalogs in zilla configuration

[jfallows]

Describe the desired outcome from the user's perspective As devops, I want to verify that my zilla configuration is self consistent, validating named bindings, guards, vaults, catalogs exist.

Acceptance criteria

• References can span across namespaces, so only log warning when naming reference not found rather than hard fail
• Check for Unreachable bindings
• Handle cross namespace references

Additional context Consider how best to handle dynamic namespace attach and detach when verifying naming reference consistency.

• [ ] https://github.com/aklivity/zilla/issues/931
• [ ] https://github.com/aklivity/zilla/issues/1161
• [ ] https://github.com/aklivity/zilla/issues/521
• [x] https://github.com/aklivity/zilla/issues/1109