Joint limits path hard coded in URDF

[mhubii]

Downstream usage would benefit from a configurable path to the joint limits file, e.g. for stricter limits (currently fixed):

lbr_fri_ros2_stack/lbr_description/urdf/iiwa7/iiwa7_description.xacro

Line 13 in c010905

<xacro:property name="joint_limits_path"

Note, when non-default limits are used, the user would then be responsible for setting the correct limits.