Add basic node launch tests for localization nodes

Summary

Added basic launch tests to the localization nodes - in particular the ndt_nodes package which contains two nodes ndt_localizer and ndt_map_publisher.

The localization_nodes package doesn't actually contain any executables so these tests occur in the ndt_nodes package. Additionally, it seems like launching the tests requires access to data in autoware_auto_avp_demo package, this cannot be added as a test dependency as the autoware_auto_avp_demo package depends also on the ndt_nodes resulting in colcon having issues creating the dependency tree. As a result, the test fails to find the package unless it has been built before and source before running the test.

Part of #394 (closed).