🎨 linter for plansys2_pddl_parser

[Rezenders]

1. Activated linter for plansys2_pddl_parser
2. Changed the extension of plansys2_pddl_parser header files from .h to .hpp
3. Added copyright information to all files
4. Formatted files with ament_clang_format --reformat
5. Formatted files with ament_uncrustify --reformat
6. Manually fixed remaining style errors
7. Added // NOLINT to lines Ground.cpp#L34 and Ground.cpp#L72 as there is a conflict between cpplint and uncrustify (check Cannot satisfy both cpplint and uncrustify ament/ament_lint#158)

[Rezenders]

@fmrico ready for review

[fmrico]

LGTM, I have been reviewing since you created the PR. It is personally useful the great you made here including in the style tests this package. I don't know when it went out of the coverage of the tests, but what really matters is that now it is fixed.
Thanks @Rezenders

Of course, merging!! 🚀