[🚀 Feature]: Use Environment Variables to set driver locations

### Feature and motivation

We discussed in the Selenium Dev Summit about having the ability to set driver location system-wide using environment variables, similar to how Java currently uses System Properties.

See #13806 

### Usage example

If we match Java System Properties, it would look like:
```
os.environ["WEBDRIVER_GECKO_DRIVER"] = path_to_geckodriver
```