Add pyproject.toml to each example

[virtuald]

Each example should have a pyproject.toml that specifies its dependencies so that users can directly use it. Then we should change the run_tests.sh to:

• Be a python script, bash is annoying for complex things
• For each project, create a new virtualenv, run robotpy sync in that virtualenv, and then run robotpy test

We would also need to create a script that can uniformly update all the robotpy versions in all the example directories so it doesn't get out of date.