Auto discovery of datasource entity-schemas

[containerpope]

Kelon should be able to read the entity_schemas from the datasources themself. This will allow way easier configuration, because users are not required to map this stuff by hand and update it if changes in the datastore occur.

Acceptance Criteria:

• Provide config flag that enables automatic entity_schema updates in the config to allow Kelon updating the mappings itself.
• Provide timer option for both settings to ensure the time basis can be configured when to sync