Add support for remote access tunnel resumption

[mobileoverlord]

On channel join, tunnels will synchronize with the server

• Tunnels that are unknown will be closed and cleaned up
• Tunnels that are requested while the device was offline will configure and open
• Tunnels that are known will be resumed
• Tunnels that are expected to be open but are missing configurations / interfaces will be closed

This also adds support for configuring a persistent data_dir where you want to write tunnel interface configurations in the peridio config. By specifying a persistent location for configurations, tunnels will resume even after device reboots.

"remote_access_tunnels": {
    "enabled": true,
    "data_dir": "/etc/peridiod"
  },