KPI Value writer and API in progress

src/common/tools/kafka/Variables.py

src/kpi_manager/service/__main__.py

src/kpi_manager/tests/test_kpi_manager.py

src/kpi_value_api/service/KpiValueApiServiceServicerImpl.py

src/kpi_value_api/tests/test_kpi_value_api.py

src/kpi_value_writer/service/KpiValueComposer.py

src/kpi_value_writer/service/KpiValueWriter.py

src/kpi_value_writer/tests/test_kpi_value_writer.py