getWebDriver timeout is too low

[aidando73]

Fixes https://github.com/testcontainers/testcontainers-java/issues/5833

I've found that a default timeout of 20, passes a sample of 10 of getWebDriver calls (whereas a timeout of 15 or 10 does not). That being said, getWebDriver could run slower in different environments, thus I've introduced a new method public RemoteWebDriver getWebDriver(int timeoutInSeconds) that allows users to specify the timeout.