Cloud NAT module does not expose `tcp_time_wait_timeout_sec`

[frits-v]

Describe the bug
The Cloud NAT module does not currently allow configuration of the TCP TIME_WAIT setting. The current google provider does support customizing this setting.

Environment
n/a

To Reproduce
n/a

Expected behavior
An input variable that exposes tcp_time_wait_timeout_sec is added and can be used to customize the TCP TIME_WAIT.

Result
n/a

Additional context
n/a

[juliocc]

Thanks for the report and PR!