Remove Closure from DevTools #305
Description
Problem statement
DevTools is not a closure-compiled demo, but it is peppered with goog calls: provides, require, and a color picker. Replace this code to eliminate issues like google/closure-library#897.
Consider https://neil.fraser.name/software/colourpicker/ or other color picker available via npm.
(Alternatively... add a compilation step into DevTools, though
Expected Behavior
Code that is never compiled with Closure should not include goog.require and goog.provide statements.
DevTools should not depend on Closure's color picker, since it is not compiled to ensure dependencies are correctly linked/available.
Recompiling main Blockly libraries, if successful, should not change whether Block Factory runs.
Actual Behavior
Recent changes in Closure broke Block Factory (and probably DevTools), even though the Blockly compilation step succeeded.
See RaspberryPiFoundation/blockly#1830, RaspberryPiFoundation/blockly#1834, RaspberryPiFoundation/blockly#668