Support ARM Raspberry Pi in GroundUpDB

[adamfowleruk]

Please start with a use case description for a USER of this work
[Who] As an IoT developer
[What] I need to store IoT information in a high speed ephemeral database on a Raspberry Pi (Arm chip)
[Value] In order to store and query lots of IoT data without damaging the SD card over time

Describe the solution you'd like
Have GroundUpDB compile on ARM (specifically Raspberry Pi 3B+ and above) - Add further protocol support in later versions

Describe alternatives you've considered
Using a heavyweight IoT message broker (MQTT) combined with a relational database for storage, and python micro service for connecting the two

Additional context
See LoRa IoT gateway and thethingsnetwork.org

[adamfowleruk]

HighwayHash issue:-

export HH_TARGET_NAME=Portable

Edit Makefile as it ignores this setting, unbelievably, so comment out the 'else' lines mentioning AVX2, and run make.

[adamfowleruk]

Related to #33 which is 64 bit arm support