add envs to set http timeout

[thousandhu]

now we can only set TLS timeout to http client. If we want to set other timeout to http client, we can't find any method. In our project, we invoke aliyun api across counties，for example from Singapore to China. We always meet different kind of timeout because of the net unstable. So we want to set different kind of timeout.

This pr add env to other four env to set different kind of timeout.

[thousandhu]

thanks @menglingwei for the review