Allow naming of gateways and transfer of the name to DK upon connection

[eely22]

Request originally from forums: https://neighborhood.bluz.io/t/proximity-detection-what-if-your-lights-could-turn-on-as-you-pull-into-the-driveway/375/4

Have a way to assign a name to the gateway, then the name is transferred to the DK upon connection. The name is then accessible to the user app through a simple get_ command. This allows the user code on the DK to know what kind of gateway it is connected to and react appropriately.