"timeout" arg missing for EnvArgs to instantiate BrowserEnv is missing

[rowingchenn]

Hi, I noticed some missing arguments in EnvArgs for instantiating BrowserGym with full configurations.

For example, timeout is not configurable in EnvArgs, and the timeout for context or page configuration can only be set by the attribute in the Task class this way.

As well as pw_chromium_kwargs, which is not that important but still incomplete for designing EnvArgs.

Hopefully, this is useful for your improvement! I've been deeply reading and reconstructing your codebase to do my experiments; I love your work, and thank you for continued updating:)