Styling for plot limits (#3917)

* Styling for plot limits and colors
* Updates to limit provider and css
* Change limits related CSS "*--upper" and "*--lower" to "*--upr" and
"*--lwr" for better parity with legacy naming;
* Refactor limit class to util
* Use new classes for sine wave generator for red-low and yellow-high
* Added modifier classes for right and below-aligned labels;
* Prevent label overlap of limits as much as possible
* Add border colors to limit labels for better visual ties to their lines
* Add documentation for limit level specification API change

Co-authored-by: Shefali Joshi <simplyrender@gmail.com>
Co-authored-by: Andrew Henry <akhenry@gmail.com>

example/generator/SinewaveLimitProvider.js

@@ -26,14 +26,26 @@ define([
 
 ) {
 
-    var RED = {
+    var PURPLE = {
+            sin: 2.2,
+            cos: 2.2
+        },
+        RED = {
             sin: 0.9,
             cos: 0.9
         },
+        ORANGE = {
+            sin: 0.7,
+            cos: 0.7
+        },
         YELLOW = {
             sin: 0.5,
             cos: 0.5
         },
+        CYAN = {
+            sin: 0.45,
+            cos: 0.45
+        },
         LIMITS = {
             rh: {
                 cssClass: "is-limit--upr is-limit--red",
@@ -94,32 +106,66 @@ define([
     };
 
     SinewaveLimitProvider.prototype.getLimits = function (domainObject) {
+
         return {
             limits: function () {
-                return {
+                return Promise.resolve({
+                    WATCH: {
+                        low: {
+                            color: "cyan",
+                            sin: -CYAN.sin,
+                            cos: -CYAN.cos
+                        },
+                        high: {
+                            color: "cyan",
+                            ...CYAN
+                        }
+                    },
                     WARNING: {
                         low: {
-                            cssClass: "is-limit--lwr is-limit--yellow",
+                            color: "yellow",
                             sin: -YELLOW.sin,
                             cos: -YELLOW.cos
                         },
                         high: {
-                            cssClass: "is-limit--upr is-limit--yellow",
+                            color: "yellow",
                             ...YELLOW
                         }
                     },
                     DISTRESS: {
                         low: {
-                            cssClass: "is-limit--lwr is-limit--red",
+                            color: "orange",
+                            sin: -ORANGE.sin,
+                            cos: -ORANGE.cos
+                        },
+                        high: {
+                            color: "orange",
+                            ...ORANGE
+                        }
+                    },
+                    CRITICAL: {
+                        low: {
+                            color: "red",
                             sin: -RED.sin,
                             cos: -RED.cos
                         },
                         high: {
-                            cssClass: "is-limit--upr is-limit--red",
+                            color: "red",
                             ...RED
                         }
+                    },
+                    SEVERE: {
+                        low: {
+                            color: "purple",
+                            sin: -PURPLE.sin,
+                            cos: -PURPLE.cos
+                        },
+                        high: {
+                            color: "purple",
+                            ...PURPLE
+                        }
                     }
-                };
+                });
             }
         };
     };