[Plot] Add user interface for filtering data

Adds plot elements and intermediary interfaces to support data filtering (removal of certain data points from a streaming feed before displaying in plot) for MCT-3886.

* Add capability FeedFilterProvider which user objects can provide in order to support filtering, by exposing:
  * User interface components by which filtering can be performed
  * A filter object which enforces filtering rules upon data points
* Add new settings for filter enabled, and filter setting
  * Added under a new category of settings called "extension" in Plot Settings, to avoid proliferating interface changes for rarely-used plot settings.
* Add new section to control area for feed filter settings (only appears if filtering is possible for a given plot; specifically, when all plotted objects offer the same FeedFilterProvider)

```
     Wrote or re-wrote unit tests (Y/N): N*
     Ran entire suite of unit tests successfully (Y/N): Y
     Verified bug fix with the described replication steps or verified the implementation meets the requirement cited (Y/N): Y
     Code coverage requirements satisfied (new code=80%, changed code=at least as high as existing) (Y/N): N
     Code review date and attendees: Code review by pull request
     Describe potential impact on other areas of the code: Plots
     Describe any test prerequisites for this fix (e.g., restart the database): N/A
     For bugs marked "Regression - Yes", describe the cause of the regression: N/A
     Did you modify any pom.xml file? If yes, did you thoroughly document your changes and reasons? N
```

Unit tests not included; deferring until merge to master branch