Fix Imagery for VERVE #266 (#3507)

* Fairly extensive refactoring to fix layout in Safari for VERVE #266

- VERY WIP at this time!
- Many instances of `height: 100%` converted or amended to include
`flex: 1 1 auto`;
- Some high-use containers like `c-so-view__object-view` converted to use
flex layout;
- Views fixed generally for sub-object view, and specifically for
Conditionals, Folder grid view and Imagery;
- Imagery background image holder converted to use absolute positioning;
- TODO: Notebook has a problem where the side nav pane isn't overlaying
in Safari - it's a JS thing, c-drawer--push isn't be replaced with
c-drawer--overlays as it should;

* CSS and markup refactoring to support addition of 'suspect' telemetry

- Remove commented code;

src/ui/components/object-frame.scss

@@ -71,8 +71,8 @@
     }
 
     &__object-view {
+        display: flex;
         flex: 1 1 auto;
-        height: 0; // Chrome 73 overflow bug fix
         overflow: auto;
 
         .u-fills-container {
@@ -84,6 +84,6 @@
 
 .l-angular-ov-wrapper {
     // This element is the recipient for object styling; cannot be display: contents
-    height: 100%;
+    flex: 1 1 auto;
     overflow: hidden;
 }