Support project names starting with gz-

[scpeters]

🎉 New feature

Part of gazebo-tooling/release-tools#718 and s subset of #239 that supports project names starting with gz-

Summary

There are quite a few changes in #239, but I'm not sure about all of them, so I split out the support for project names starting with gz- into this pull request (with a slightly different implementation).

Test it

I've tested this a bit with gazebosim/gz-utils#57 and gazebosim/gz-math#420 (without the gz-cmake3 project name), and it seems to be working.

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• 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.

[chapulina]

Works as advertised. I just have one suggestion that should make it easier to completely remove ignition later.