*  Separate generated metadata into their own, top-level package: pkg/metadata

- Introduce builder pattern to the core schema types that are used by pkg/metadata,
  to ensure runtime immutability after build.
- Move the Kubernetes related machinery to their own package, pkg/kube/source, to
  separate it from core Kubernetes related abstractions and utility code.
- Bolster tests and cleanup tests accordingly.

* Add builder support to InMemory snapshot. (#3)

* Add builder support to InMemory snapshot.

* Clone resurces as well.

* Use proto.Clone, instead of manual copying.

* Add a testing server for MCP. (#4)

* Add a testing server for MCP.

* Add overridable port field.

* Don't parse the port number.

* Minor bug & linter fix (#6)

* Fix a bug in the in-memory source implementation where the item itself
was missing when publishing already-existing items during the initial
sync phase.

* Fix lint issue.

* Updates to acommodate merge.

* Update Gokg.lock.

Add concourse install pipeline

* Utilities package common data types

* Lint