Incorrect default for 'Idle-Timeout'

[jellonek]

erGW version

2.3.0

Erlang/OTP version

23.2.7

Description

Optional functionality behind Idle-Timeout setting on the APN level has a default value of 8h, what makes it non optional by default.
It is set in

ergw/src/ergw_config.erl

Line 46 in e429a07

{'Idle-Timeout', 28800000} %% 8hrs timer in msecs

Current behavior

If nothing is provided in the config - code will default to linked above 8h.

Expected behavior

• it is optional functionality - so it should default to infinity
• or at least this should match any of our use cases (if we are using this variable - we are setting there 12h always)