[REFACTOR] Reduce walltime of examples

[ravinkohli]

Currently, the examples are all searching for 5 minutes which I think for the datasets we use is too long. Especially for the purpose of demonstrating the functionality of AutoPyTorch, I think its a bit excessive. We should reduce it to 100 seconds for each search as this will also greatly reduce the time it takes to pass the build-and-deploy check for each PR. Its not urgent but it will be useful.

[eddiebergman]

It's a good idea, as the number of examples grow, it gets annoying to test them. At this point I just let the automated doc building do all the work but when running them manually it's a bit annoying.