CORE-4433 Updated NewToolRequestFormView with toolRequestServlet proxy.

Remonde obsolete newToolRequest constant, making CommonAppConstants obsolete.
Constants::CLIENT is now just an instantiation of DEClientConstants.
CORE-4433 Updated response handling in NewToolRequestFormViewImpl.

Added stripTags call to SubmitCompleteHandler since the new toolRequestServlet proxy endpoint returns a response with "pre" tags around the JSON results.
The new endpoint also now uses the standard "success" boolean instead of an "error" key in its JSON response.
Updated the info message box title for successful submissions.