Settings Implementation

Allows full configuration of Network, PIN and Door without editing or
even creating CFG files.
-Network will generate random MAC and use DHCP by default setting and
store into EEPROM if no NETWORK.CFG file is present
-Default pins.cfg file generated if not present
-RSV pins can not be assigned via Settings
-Free configuration of doors.cfg via web page, device updates only with
properly formed JSON
Entropy is licensed under GPLv3 which is incompatible with GPLv2 used for this project. If we link to Entropy then we probably need to upgrade the license for this project to GPLv3, which is not an exercise I want to undertake.
Either Entropy needs to be replaced with a different solution or we can skip the "random MAC address" feature for now. 
Suggestion: a) Use another true random library with a license compatible with GPLv2. Or b) Use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.