Use Waymo Protos Directly

[pimpale]

What changes do you make in this PR?

In this PR, we remove the dependency on waymo-open-dataset-tf-2-11-0 by including the Protobuf definitions inside the scenarionet repository itself.

• Please describe why you create this PR

This allows users to avoid having to install waymo-open-dataset-tf-2-11-0, which has many dependencies like numpy==1.5.1 which are outdated.

Checklist

• [x] I have merged the latest main branch into current branch.
• [x] I have run bash scripts/format.sh before merging.
• Please use "squash and merge" mode.

[pengzhenghao]

@QuanyiLi Do we have license issue here?

[pimpale]

The protobuf definitions are under Apache 2.0, so it should hopefully be fine. I'm not sure under which license scenarionet is under though.

[QuanyiLi]

Like MetaDrive, ScenarioNet can use Apache 2.0 as well. So there won't be conflicts.