[CT-2526] Create Metric node for measures with create_metric: true during parsing

[QMalcolm]

SemanticModels have Measure sub-objects. Measures can be defined with create_metric: true. If a Measure is defined with this, we need to create a Metric node for the Measure during parse time. We do have a prototype of one way this could be done, #7187, if inspiration is needed.

Blocked by:

• [CT-2522] Redefine Metric node for the Manifest and update parsing #7500
• [CT-2521] Define SemanticModel node for the Manifest #7499

[jtcohen6]

There's an analogy here for models & generic tests

Model

• columns (attribute of Model node)
  • tests --> creates Test nodes

SemanticModel

• measures (attribute of SemanticModel)
  • create_metric --> creates full-fledged Metric nodes

There are some simple rules for copying over the measure's attributes into the new Metric node

For partial parsing: We always need to schedule metrics for re-parsing if there is a change to one or multiple SemanticModels that the metric depends on. This holds true for metrics defined explicitly, and implicitly via create_metric: true.