Refactor custom_controller

[JustinShih0918]

1. Review code from src/custom_controller/src/custom_controller.cpp and src/custom_controller/include/custom_controller/custom_controller.hpp
2. rename the controller base on the feature and what the controller can do, please discuss with @JustinShih0918 .
3. refactor the code with the new name and new namespace.
4. refactor the redundant if-else or local variable, align the variable name and function name.
5. fix CMakeLists & package.xml to make it build-able
6. fix custom.xml so that the system can find the controller
7. change the name of these line, see if anything went well in simulator
   src/navigation2_run/params/nav2_params_default.yaml#L126-L173
8. if everything works fine, change on machine param src/navigation2_run/params/nav2_params_11.yaml & src/navigation2_run/params/nav2_params_14.yaml
9. test on machine
10. update readme