Adding rssi

[caguero]

🎉 New feature

Summary

This PR adds the rssi value to the message sent between two robots using the comms infrastructure. This can be useful for estimating the range between the robots.

Test it

• Run the tests.
• Run the example:

1. Launch Gazebo:

ign gazebo -v 4 <your_ws>/src/ign-gazebo/examples/worlds/rf_comms.sdf

2. Launch a subscriber:

ign topic -e -t addr2/rx

3. Launch a publisher:

cd <your_ws>/src/ign-gazebo/examples/standalone/comms
mkdir build && cd build
cmake ..
make
./publisher addr2

You should observe messages on the subscriber terminal with the new rssi field.

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸🔸

[iche033]

looks good to me. Just one very minor comment

[codecov]

Codecov Report

Merging #1482 (91cf690) into ign-gazebo6 (2a419fe) will not change coverage.
The diff coverage is n/a.

❗ Current head 91cf690 differs from pull request most recent head f2359bc. Consider uploading reports for the commit f2359bc to get more accurate results

@@             Coverage Diff              @@
##           ign-gazebo6    #1482   +/-   ##
============================================
  Coverage        33.58%   33.58%           
============================================
  Files               44       44           
  Lines             2260     2260           
============================================
  Hits               759      759           
  Misses            1501     1501           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2a419fe...f2359bc. Read the comment docs.