Block traffic during first connection.

Set up routes to UDP unlimited server (since openvpn hasn't finished, it
simply blocks traffic) and also DNS server to 10.41.0.1.

These values correspond to current leap_platform configuration (https://github.com/leapcode/leap_platform/blob/7bc79e68e5ca913d1d2843c48cde8f946feed09c/puppet/modules/site_openvpn/manifests/init.pp)
Set up early routes on boot too.
Finish VoidVpnLauncher activity.

It was remaining there, with an empty layout.
A bit of refactoring.

ConfigHelper checks for IllegalArgumentException (trace from play
store).
EIP location code has been splitted a bit.

I'd like to extract OVPNGateway out from EIP, but that's not an easy job
and this branch is already lasting to much hehehe.
Merge branch 'feature/Early-routes-#5816' into develop