add ROS setup and microros local setup to bashrc (#392)

* add ROS setup and microros local setup to bashrc

adding the setup.bash files for both ROS2 and micro-ros to the .bashrc reduces the complexity of the tutorial and  makes it easier to understand

* Apply ralph-lange's suggestions

Co-authored-by: Ralph Lange <ralph-lange@users.noreply.github.com>

* Add missing empty line

---------

Co-authored-by: Antón Casas <antoncasas@eprosima.com>
Co-authored-by: Ralph Lange <ralph-lange@users.noreply.github.com>

Author: 3 people

_docs/tutorials/core/first_application_linux/index.md

@@ -63,6 +63,14 @@ source install/local_setup.bash
 ```
 {% include first_application_common/agent_creation.md %}
 
+### Add micro-ROS environment to bashrc (optional)
+
+You can add the ROS 2 and micro-ROS workspace setup files to your `.bashrc` so the files do not have to be sourced every time a new command line is opened.
+```bash
+echo source /opt/ros/$ROS_DISTRO/setup.bash >> ~/.bashrc
+echo source ~/microros_ws/install/local_setup.bash >> ~/.bashrc
+```
+
 ## Running the micro-ROS app
 
 At this point, you have both the client and the agent correctly installed in your host machine.