Add project() call to examples

[chapulina]

🦟 Bug fix

Similar to

• Add project() to examples gz-physics#322
• Add project() to examples and remove hard-dependency on Ogre1 gz-gui#345

Summary

This is needed to silence CMake warnings like this:

33: CMake Warning (dev) in CMakeLists.txt:
33:   No project() command is present.  The top-level CMakeLists.txt file must
33:   contain a literal, direct call to the project() command.  Add a line of
33:   code such as
33: 
33:     project(ProjectName)
33: 
33:   near the top of the file, but after cmake_minimum_required().
33: 
33:   CMake is pretending there is a "project(Project)" command on the first
33:   line.
33: This warning is for project developers.  Use -Wno-dev to suppress it.

These warnings show up on Jenkins CI since we migrated from Bionic to Focal:

• Default to Focal for CI gazebo-tooling/release-tools#565

There are also CMP0072 warnings coming from the examples. I suspect that's coming from ign-gui because it currently links to ignition-rendering-ogre, but it shouldn't anymore after gazebosim/gz-gui#345.

Checklist

• Signed all commits for DCO
• Added tests
• 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.

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[codecov]

Codecov Report

Merging #1274 (5703854) into ign-gazebo3 (0d00cc1) will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           ign-gazebo3    #1274   +/-   ##
============================================
  Coverage        77.25%   77.25%           
============================================
  Files              227      227           
  Lines            13535    13535           
============================================
  Hits             10457    10457           
  Misses            3078     3078           

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[osrf-triage]

This pull request has been mentioned on Gazebo Community. There might be relevant details there:

https://community.gazebosim.org/t/new-ignition-releases-2022-03-01-citadel-edifice-fortress/1313/1

[osrf-triage]

This pull request has been mentioned on Gazebo Community. There might be relevant details there:

https://community.gazebosim.org/t/new-ignition-releases-2022-04-13-fortress-edifice/1367/1