Indicators api (#1837)

* [API] Added Indicators API

* [Indicators] Converted Follow Indicator to new Indicators API

* [Indicators] Converted URL Indicator to new Indicators API

* [Indicators] Changes to some legacy indicators for compatibility with new Indicators API

* [Indicators] Addressed code review items from https://github.com/nasa/openmct/pull/1837

* Updated tests for URL Indicator

* Adding Indicator API spec

* Address linting issues

* Switched to direct DOM manipulation rather than template compilation to avoid an unnecessary extra holder element

* Updated documentation to reflect changes to API

* Indicators api styling (#2076)

Updated styling for Indicators

* Update API TOC

* Fix color of items w-mct-example areas of Style Guide

Fixes #1837

* Status class refactoring and cleanups

Fixes #1837
- Significant cleanups and name refactoring to allow more
concise selector definitions, with changes in js, html and scss files;
- Updates in Style Guide > Status page, with some content
reorganization and clarification;

* Corrected out of date API

* de-zeptoed Indicator API test spec

* Remove promise from URLIndicator

* Separated legacy indicators support

* Updated Indicator specs to Jasmine 3

* Fixed checkstyle and lint issues

* Moved legacy indicators support to adapter folder

* Various fixes for Indicators

Fixes #1837
- Added SASS constants for Indicator colors;
- Removed commented code;
- Removed unused indicator classes from _messages.scss
- Fixed missing s-status-on class;

* Significant revisions to Style Guide Indicators content

Fixes #1837
- Better documentation including recommendations;
- Better and more concrete examples;

* Style Guide example tweaks

Fixes #1837

* Refinement to Style Guide Status and Limits content

Fixes #1837
- More detail and clarification on Status and Limits;

* Cleanup code

Fixes #1837
- Remove commented styles;
- Line return refinements;

platform/commonUI/themes/espresso/res/sass/_constants.scss

@@ -3,6 +3,8 @@ $colorBodyBg: #333;
 $colorBodyFg: #999;
 $colorGenBg: #222;
 $colorStatusBarBg: #000;
+$colorStatusBarFg: #999;
+$colorStatusBarFgHov: #aaa;
 $colorKey: #0099cc;
 $colorKeySelectedBg: #005177;
 $colorKeyFg: #fff;
@@ -55,7 +57,7 @@ $colorTransLucBg: #666; // Used as a visual blocking element over variable backg
 
 // Foundation Colors
 $colorAlt1: #ffc700;
-$colorAlert: #ff3c00;
+$colorAlert: #ff9900;
 $colorWarningHi: #cc0000;
 $colorWarningLo: #ff9900;
 $colorDiagnostic: #a4b442;
@@ -72,7 +74,6 @@ $colorObjHdrTxt: $colorBodyFg;
 $colorObjHdrIc: lighten($colorObjHdrTxt, 20%);
 $colorTick: rgba(white, 0.2);
 $colorSelectableSelectedPrimary: $colorKey;
-//$colorSelectableSelectedSecondary: pushBack($colorSelectableSelectedPrimary, 20%);
 $colorSelectableHov: rgba($colorBodyFg, 0.3);
 
 // Menu colors
@@ -114,11 +115,10 @@ $colorInspectorSectionHeaderFg: pullForward($colorInspectorBg, 40%);
 
 // Status colors, mainly used for messaging and item ancillary symbols
 $colorStatusFg: #ccc;
-$colorStatusDefault: #ccc;
+$colorStatusDefault: #999;
 $colorStatusInfo: $colorInfo;
 $colorStatusAlert: $colorAlert;
-$colorStatusError: #d4585c;
-$colorStatusAvailable: $colorKey;
+$colorStatusError: #da0004;
 $colorStatusBtnBg: $colorBtnBg;
 $colorProgressBarOuter: rgba(#000, 0.1);
 $colorProgressBarAmt: $colorKey;
@@ -127,6 +127,12 @@ $progressBarStripeW: 20px;
 $shdwStatusIc: rgba(black, 0.4) 0 1px 2px;
 $animPausedPulseDur: 500ms;
 
+// Indicator colors
+$colorIndicatorAvailable: $colorKey;
+$colorIndicatorDisabled: #444;
+$colorIndicatorOn: $colorOk;
+$colorIndicatorOff: #666;
+
 // Selects
 $colorSelectBg: $colorBtnBg;
 $colorSelectFg: $colorBtnFg;