Add project() to examples and remove hard-dependency on Ogre1

[chapulina]

🦟 Bug fix

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's still another warning coming from ign-rendering, tracked here:

I added a workaround for the warning coming from ign-rendering until we fix it upstream

• CMake policy CMP0072 gz-rendering#360

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 #345 (1f7164b) into ign-gui3 (803bf23) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           ign-gui3     #345   +/-   ##
=========================================
  Coverage     66.83%   66.83%           
=========================================
  Files            25       25           
  Lines          2964     2964           
=========================================
  Hits           1981     1981           
  Misses          983      983           

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[chapulina]

@osrf-jenkins run tests now that the buildfarm is back, please

[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-2022-01-24-citadel-edifice-fortress/1241/1

[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-2022-03-01-citadel-edifice-fortress/1313/1