feat(routeoptimization): New code samples

[bshi]

Description

Fixes #<ISSUE-NUMBER>

Note: Before submitting a pull request, please open an issue for discussion if you are not associated with Google.

Checklist

• [X] I have followed Sample Format Guide
• [X] pom.xml parent set to latest shared-configuration
• [X] Appropriate changes to README are included in PR
• [X] These samples need a new API enabled in testing projects to pass (let us know which ones)
  • routeoptimization.googleapis.com
• [N/A] These samples need a new/updated env vars in testing projects set to pass (let us know which ones)
• [X] Tests pass: mvn clean verify required
• [X] Lint passes: mvn -P lint checkstyle:check required
• [X] Static Analysis: mvn -P lint clean compile pmd:cpd-check spotbugs:check advisory only
• [X] This sample adds a new sample directory, and I updated the CODEOWNERS file with the codeowners for this sample
• [X] This sample adds a new Product API, and I updated the Blunderbuss issue/PR auto-assigner with the codeowners for this sample
• [X] Please merge this PR for me once it is approved