Servo Developer Experience Improvements

Servo is a cross-platform, open-source browser engine that next-generation browsers can be built on, including the Verso browser project. However, the current developer experience is lacking in some ways, including CI/CD, benchmarks, and documentation for integration in downstream projects. While the Servo project these things currently, ongoing maintenance to keep them up to date, as well as creation of new documentation and tutorials to aid newcomers to the project, is a task that always needs work. In order to make integration with Servo easier for both the Verso project, as well as new projects that want to use it, this project aims to bring modern enhancements and new content to these areas.