Splitted apply_model_schema_on_table method #138
Splitted apply_model_schema_on_table method into three more consistent parts regarding the different steps of migrating, loading slqlachemy events and reloading.
Originally, the apply_model_schema_on_table gathered either migrations, sqlalchemy ORm events registration and reload check. The execution of the whole method was conditionned by the registry.loadwithoutmigration attribute although sqlalchemy events registration whould not depend on whether system should perform a migration or not but must instead be executed at any time.
This PR is intented at proposing a better separation between migration and sqlalchemy orm events registration.