Fix controllers.yaml loading

[cpr-fer]

Followup of #62

The movegroups moveit controllers parameter does not work with the same approach as other yaml files. As such ReplaceString() cant be used and the joint prefixes have to be hardcoded. This makes multi-robot setups harder to use and should be fixed

This does not work as moveit expects a dictionary and not a file for the parameter.

moveit_controllers_file = PathJoinSubstitution(
    [
        FindPackageShare("irc_ros_moveit_config"),
        "config",
        "moveit_controllers.yaml",
    ]
 )
moveit_controllers = ReplaceString(
    source_file=moveit_controllers_file,
    replacements={
         "<namespace>": namespace,
         "<prefix>": prefix,
    },
)

[cpr-fer]

Was fixed in #30