power_state_change: convert an int input for delay to string, improve doc

this adds 'timeout' to the documentation for power_state_change, and
supports delay being an integer or a string.  This is so that yaml
can contain:
 delay: 30
rather than
 delay: "+30"
or
 dealy: "30"
fix DataSourceAzure incompatibility with 2.6
fix power_state_change config module so that example works, improve doc