Use logname var instead of the inline string "opw" everywhere

[JeroenDM]

First merge #76 and rebase.

[JeroenDM]

I also tested this locally to circumvent CI not fixed yet in this branch.

[JeroenDM]

(Looking forward to the day we can compile with c++20 and make LOGNAME and std::string again, but that's just nitpicking I guess :) )

[simonschmeisser]

I had a quick glance at MoveIt PlanningScene and there it is const std::string LOGNAME, is there a real difference between either of them?

[JeroenDM]

I had a quick glance at MoveIt PlanningScene and there it is const std::string LOGNAME, is there a real difference between either of them?

Not really, I once got it as a review comment to use constexpr and therefore updated the docs:
moveit/moveit.ros.org#474.

But in hindsight it's a clear example of me taking nitpicking too far... :) I guess in general C++ programmers have a tendency to over optimize.

[simonschmeisser]

I guess in general C++ programmers have a tendency to over optimize.

Agreed. Seriously, I don't actually want to know the difference and I hope the compiler does it's job and the end result is just the same ...