New default needed for tool_consumer_instance_name in sakai.properties

When testing an LTI tool on the nightly experimental server, the tool failed to launch and the following error appeared: "A required parameter (tool_consumer_instance_name) was missing."

Apparently, there is a basiclti.consumer_instance_name = value that can be set in sakai.properties. However, the default is "none." While most LTI tools don't use this parameter, some of them (like the one being tested recently) do require it. We would like to have a new default value added to sakai.properties, so that the consumer name is automatically populated with something appropriate (e.g. server url or similar).  

There are three values and here is how Sakai computes a default if they are not explicitly listed in sakai.properties:

tool_consumer_instance_name - properties serverName or properties serverUrl or "localhost.sakailms"

tool_consumer_instance_guid - a Sha256 of the name

tool_consumer_instance_description - The same as the name