A timeout config value is added for each collector which uses requests
to fetch data, and this value is used for any requests calls.
Without a timeout a request may stall indefinitely and
os-collect-config will stop polling.
A timeout default of 10 seconds is chosen as the default. This is used
for both the connection timeout and the read timeout.
Change-Id: I4ad0065b5a85393105c6385a15653d7204b4f880
Closes-Bug: #1600652