Added option to publish SRDF file.

[v-marsh]

Added argument to the launch file that can toggle the ability to publish the contents of the SRDF on the topic /robot_description_semantic. This allows the launch file to be used with custom moveit2 projects without having to source the SRDF for every launched node.

See following link for details: https://moveit.picknik.ai/humble/doc/examples/urdf_srdf/urdf_srdf_tutorial.html#string-topic-specification

Note: The default behaviour of not publishing this topic has been maintained, but now users have the option publish it if needed.

[v-marsh]

Because #1036 only applies to the main branch which fails to build on ros2 humble. This request applies that same change to the humble branch which is useful for projects still running on humble due to its long term support.

[fmauch]

Sorry, my comment was misleading. I was basically making two statements. The first being the backport of #1036. I'll make my second statement in-code to make it clear.

[v-marsh]

I agree with keeping the default value as True. The only reason I initially set it to False was to avoid changing to default API in case there is some obscure situation where publishing it resulted in certain worksflows failing to complete.