[Python] Support connection/read timeout

[mbohlool]

Description

There is no way to pass a timeout for a request (both connection and read).

Swagger-codegen version

2.2.2-SNAPSHOT

Suggest a Fix

urllib3 that is used in python client supports Timeout for connection and read. The timeout object need to be passed through ApiClient to RestClient to urllib3.

Another option is to add it to configuration though I prefer per request timeout.

[mbohlool]

The fix would be similar to #4166. I will send a PR. you can assign this to me.