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* Corrected out of date API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;

src/MCT.js

@@ -30,7 +30,8 @@ define([
     './plugins/plugins',
     './ui/ViewRegistry',
     './ui/InspectorViewRegistry',
-    './ui/ToolbarRegistry'
+    './ui/ToolbarRegistry',
+    './adapter/indicators/legacy-indicators-plugin'
 ], function (
     EventEmitter,
     legacyRegistry,
@@ -41,7 +42,8 @@ define([
     plugins,
     ViewRegistry,
     InspectorViewRegistry,
-    ToolbarRegistry
+    ToolbarRegistry,
+    LegacyIndicatorsPlugin
 ) {
     /**
      * Open MCT is an extensible web application for building mission
@@ -192,6 +194,15 @@ define([
          */
         this.telemetry = new api.TelemetryAPI(this);
 
+        /**
+         * An interface for creating new indicators and changing them dynamically.
+         *
+         * @type {module:openmct.IndicatorAPI}
+         * @memberof module:openmct.MCT#
+         * @name indicators
+         */
+        this.indicators = new api.IndicatorAPI(this);
+
         this.Dialog = api.Dialog;
 
     }
@@ -266,6 +277,9 @@ define([
 
         legacyRegistry.register('adapter', this.legacyBundle);
         legacyRegistry.enable('adapter');
+
+        this.install(LegacyIndicatorsPlugin());
+
         /**
          * Fired by [MCT]{@link module:openmct.MCT} when the application
          * is started.