Custom python API for easy to use launch files

[afxalz]

[afxalz]

• Added a launch helper that provides easy utility functions to add:
  • launch arg to get arguments at runtime
  • a custom_config arg to get config file names same as ROS1
  • loading of all yaml files in a directory
  • loading of a single yaml file
  • remaps
  • verbose output of the params being used for node creation

[afxalz]

TODO:

• test for easy testing the helper module
• example for one of the complex nodes from MRS
• function to add remaps as list of tuples
• function to add more than one node in the same container
• function to add more than one custom_config-like arguments