Add description how to add duration parameters in controller manager tutorial

[2scholz]

This is in relation to moveit/moveit#785

I added an example of how to set these parameters.

I also added a description that details what these parameters do, due to the fact that I could not find any previous documentation of them in any of the tutorials.

[v4hn]

Hm, I don't think these parameters are relevant for the fake controller manager, so this feels like the wrong place for this information.
Could you add it here instead?

[2scholz]

Seems reasonable. I added the parameters to the existing YAML file examples for the arm and the gripper and provide a description of them below the examples.

[v4hn]

I added the parameters to the existing YAML file examples

That sounds like a good idea at first, but please don't.
These parameters are optional and the defaults are good enough for almost all users.
I think you already have a rough idea how confused most newcomers are by MoveIt's complexity, no need to fire an even longer yaml at them (at first).
So this deserves its own section below, possibly with its own example.

[2scholz]

I made the suggested changes and added a short example.

[2scholz]

I added a short description of the differences between the controller-specific values and the global ones.
I also rebased the branch, because the file was moved to a different directory recently.

[mlautman]

@v4hn

[v4hn]

Thanks @2scholz !