Adds VPN IP partial matching feature

[sagech]

If your VPN IP is 1.2.3.4, you may configure routes.json with any of the following, for example:

{
  "remotes": {
    "3.4.5": [
      "1.2.3.4",
      "5.6.7.8"
    ]
  }
}

Which matches VPN IPs 2.3.4.5, 3.4.5.6, 1.3.4.5, etc