Debt Advice Locator Integration: Update Gemfile

* Adds dependency on debt_advice_locator
* Updates dough-ruby to 3.2.0 or better
Debt Advice Locator Integration: set parent controller to embedded tools controller
Debt Advice Locator Integration: Tool mount point + routes with feature block.
Debt Advice Locator Integration: add engine migration to schema.rb
Debt Advice Locator Integration: update bower.json.erb
Debt Advice Locator Integration: Add RequireJS path to engine config.
Debt Advice Locator Integration: Add a minimal RSpec integration test