Update ros2_control usage to recent deprecations

[sjahr]

Addresses this deprecation warnings

[Deprecated] Passing the robot description parameter directly to the control_manager node is deprecated. Use '~/robot_description' topic from 'robot_state_publisher' instead.

and this deprecation warning(removed in most recent release because it was so old):

Parsing of optional initial interface values failed or uses a deprecated format. Add initial values for every state interface in the ros2_control.xacro. For example:
[ros2_control_node-5] <state_interface name="velocity">
[ros2_control_node-5]   <param name="initial_value">0.0</param>
[ros2_control_node-5] </state_interface>

[sjahr]

Closing this as it is outdated