Feature Highlighting

[james-rae]

This will likely require some upfront design work.
Things to consider

• GeoAPI does have a highlight layer, but it is essentially untested
• In RAMP2, the "fogging" of the map behind the highlight was done by directly manipulating the SVG that represented the ESRI map. If we do the same, will need to see if things are different in ESRI 4, and be aware that WebGL may be used instead of SVG.
• An API function to request a highlight sounds like a fine idea
• Functions to get individual geometries from a layer already exist in GeoAPI

Related design discussion #837

[dan-bowerman]

Engage the UI/UX team (Aleks) for suggestions on moving forward.