Allow passing a widget class to SourceColumn. This makes
using lambdas to render model column unnecesary and are
mostly removed too.
Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>
Instead of inserting the path of the apps into the Python app,
the apps are now referenced by their full import path.
This app name claves with external or native Python libraries.
Example: Mayan statistics app vs. Python new statistics library.
Every app reference is now prepended with 'mayan.apps'.
Existing config.yml files need to be updated manually.
Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>
