Original work by @ourairquality
* Sysparam threadsafe and SPI access
* Sysparam test cases
* Fix for negative int8
* Sysparam getting bool without memory allocation. Bool tests.
* SPI flash refactoring.
* Extract common spiflash.c into core.
* Use spiflash.c in sysparam.
* Use memcpy in spiflash.c insted of hand-written version.
* Tests for spiflash.c
