Type.forName not namespace safe

[yippie]

If packaged, Actions and Finalizers use an API that cannot access classes outside of the same package. Salesforce Documentation on the Type.forName warns of this and suggests using an alternative API https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_methods_system_type.htm#apex_System_Type_forName

This adds new Apex_Class_Namespace fields and uses the more explicit and safer version of Type.ForName. I also included a fallback to make sure no existing functionality is lost.

Expected Behavior

Custom action to run

Actual Behavior

Non-namespaced action classes will not be found or used

Steps to Reproduce the Problem

1. Package apex-trigger-action-framework in a Namespaced package.
2. Create a Trigger action handler that is not namespaced
3. Create a trigger action for the handler
4. Do DML to cause the action to happen

[yippie]

Fixed by #149