[Telemetry] Add metadata and formatter support

Add TelemetryMetadataManager which assists developers in interrogating
telemetry metadata to find values that are useful for them.

Add TelemetryValueFormatter to simplify the parsing (retrieval of numerical
values) and formatting (retrieval of displayable string value) of datums.

https://github.com/nasa/openmct/issues/1310

src/MCT.js

@@ -192,7 +192,7 @@ define([
          * @memberof module:openmct.MCT#
          * @name telemetry
          */
-        this.telemetry = new api.TelemetryAPI();
+        this.telemetry = new api.TelemetryAPI(this);
 
         this.TimeConductor = this.conductor; // compatibility for prototype
         this.on('navigation', this.selection.clear.bind(this.selection));