#23 remove unused class
#23 refactor DataSourceConfigurationRepository
#23 refactor db test. release db connection for each test case.
#23 refactor ExternalDataRepository
#23 refactor SqlNoteRepository
#23 refactor SqlNoteRepository
#23 refactory SystemConfigurationRepository
#23 refactory SystemConfigurationRepository
#23 remove empty lines
#23 move core domain classes
#23 move query classes
#23 remove unused class
#23 move not domain classes
#23 move system config class
#23 refactory DataSourceConfigurationRepository
#28 implements rest api
#28 select default datasource if localstorage is empty.
#28 move dataSource selector for visible