refactor `move_base` action server

[minhnh]

• move initialization of move_base action client to init
• use callbacks to interact with move_base action
• load navigation goal YAML file once in init
• check only result state as result is always None

Checklist:

• [x] My code doesn't contain unnecessary comment blocks (e.g. unused code, templates of package.xml or CMakeLists.txt)

[minhnh]

making WIP to resolve Codacy issues

[minhnh]

@alex-mitrevski this PR is now ready for review.