Implement `component.properties`

[maennchen]

Proposed properties:

Important

Let me know if what you think about them :) or if you want more or less than the proposed

Mix dependency metadata:

"properties": [
  {"name": "mix:runtime", "value": "true"},
  {"name": "mix:optional", "value": "false"},
  {"name": "mix:only", "value": "dev,test"},
  {"name": "mix:targets", "value": "host"}
]

Source: Already available in component map from MixFile fetcher