Inherited Risk & Other Metrics: Totalling for Different Views

### Current Behavior:
Currently, "Inherited Risk Score" is displayed per project, and for the Portfolio as a whole.
"Projects at Risk" count (etc) is displayed only for the Portfolio.

### Proposed Behavior:
Display metrics for different criteria
* **Team** (coming in v3,9 per #140). It would be a security issue (information leakage) if metrics for the whole Portfolio were displayed to a team that only has access to a subset of projects... and would give reduced functionality for the team (as they do not know the metrics for their own subset of projects).
* **Tag**. See #238.
* **Active/Inactive** (released in v3.6). Using Inherited Risk as an example. if Portfolio Risk is 10,000 and 9,500 comes from Inactive Projects, then being able to filter metrics for "Active" makes a huge difference!
* **Scope** See #449 eg, metrics excluding test components
* **Type**

Review the current Portfolio and project metric views, then read related issues #140, #238, and #449 to understand the planned Team, Tag, and Scope criteria. Clarify how Active/Inactive and Type filters should combine with access restrictions; done should include correctly totaled metrics for each supported view without leaking inaccessible projects.

Written by the indexing model from the issue text.