[DRAFT] Prepare for 10.0.0 release

[caguero]

🎈 Release

Preparation for 10.0.0 release.

Comparison to 10.0.0~pre2: gz-gui10_10.0.0-pre2...gz-gui10

Checklist

• Asked team if this is a good time for a release
• There are no changes to be ported from the previous major version
• No PRs targeted at this major version are close to getting in
• Bumped minor for new features, patch for bug fixes
• Updated changelog
• Updated migration guide (as needed)
• Link to PR updating dependency versions in appropriate repository in gazebo-release (as needed):

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]

there is just one minor url link fix in #714, not sure if it's worth adding to the changelog. Fine without it.

[caguero]

there is just one minor url link fix in #714, not sure if it's worth adding to the changelog. Fine without it.

Thanks. I noticed we were missing a few changelog entries. Added in ad08edd.