Offline Support: Investigate Reachability issues.

[diegoreymendez]

This issue was spawned off this PR.

In that PR I noticed Reachability isn't calling the network availability closures reliably. In fact they're only called once apparently.

Investigate how this can be resolved.

Options to Consider:

1. Investigate the different mechanisms we use in the App for reachability.
2. Consider using this library, or another similar library.

On NWPathMonitor:

We can't exclusively use NWPathMonitor because it's only supported in iOS 12+, but we could consider using it conditionally for now so that when we drop support for earlier iOS versions, we can fully switch to it.

[yaelirub]

might be helpful: WWDC 2012 session 706 networking best practices

[diegoreymendez]

This issue seems to be known: tonymillion/Reachability#171

[diegoreymendez]

I've tested this using a device instead of the simulator, and it's working fine.

Closing this issue for now.