Add NetworkStateReceiver

**Is your feature request related to a problem? Please describe.**
As of now, the user can't use the app without the internet and she/he gets a SnackBar message saying: "Please check your internet connection." And the problem is that when the user turns mobile data / wifi on, she/he needs to update the current fragment by clicking on it. It would be more user-friendly if the data would be loaded automatically.

**Describe the solution you'd like**
A NetworkStateReceiver that will notify all ViewModels when there is an internet connection and inside of each ViewModel it should refresh / try to load data one more time.

**Describe alternatives you've considered**
We could also let the user save all the data and use the app offline, but I think that this need to be discussed on Slack and even if implement that, we would still need a NetworkStateReceiver for at lease MembersFragment.

**Gif**