This PR attempts to make VPN startup architecture more resilient. It introduces 4 main changes:

New process structure

• One main NodeJS process,
• who manages internally the OpenVPN binary
• who serves the static files

Global ENVs are polled, not pushed

Instead of waiting to be reseted, the VPN will poll a DAPPMANAGER API for global ENVs:

GET http://dappmanager.dappnode/global-envs/hostname

RETURNS "hostname"

GET http://dappmanager.dappnode/global-envs/internal_ip

RETURNS "internal_ip"

• Change DAPPMANAGER initializeDb to not restart the VPN
• Make sure logs persist after the VPN process.exit(1) itself

Startup script in Javascript

Write the entrypoint inside the NodeJS app, so it can be smarter and not stall. It can also report it's status via the NodeJS app to the DAPPMANAGER > ADMIN:

GET http://vpn.dappnode/status

RETURNS "Polling configuration" ||
        "DAPPMANAGER not available" ||
        "OpenVPN error"

Deprecate the loginMsg file

Instead of waiting for a file to exist, periodically query the VPN status endpoint and eventually request the admin credentials to be generated.