Filter out components with `buildable: False`

[nc6]

Describe the bug
When a component (e.g. a test suite) is marked as 'buildable : False', tricorder fails with an error because the component isn't buildable.

To Reproduce
Try to build a project with a buildable : False component.

Expected behavior
I would expect that component to be excluded from the repl, but everything else to build correctly.

Environment

• OS name + version: nixos-unstable
• Version of the code: 91aa6a6