The BACKGROUND firewall chain has been recently added. We want to
be able to turn it off in case of contingencies with a device-config
flag flip.
The flag is assumed to be boot-stable and its value is read at boot.
When the flag is off, we ignore any operation on this firewall chain.
Additionally, this chain is always considered disabled on versions
upto UPSIDE_DOWN_CAKE.
Note: All firewall chains are in disabled state at boot by default.
Test: atest FrameworksNetTests
Test: Manually, using adb shell device_config commands.
Bug: 331484830
Change-Id: I9ccc483e02e27a584da6714931466a9f2ec95ca9
724d8972e4