set default instance for effect type `effect.this` to `e`

NYI: UNDER DEVELOPMENT: This is a manual work-around to automatically install
default effects. It should be replaced by a effect configuration file that
is defined locally to a fuzion project or globally to the fuzion installation
the defines the default effects to be used. The DFA should then automatically
determine the required effects and create code to instate them at the beginning
of an application.