Rewrite all the integer math operations with const input parameters to
use PROGMEM properly (pgm_read_xx or memcpy_P), and move all the EC
order and generators and SHA OIDs to PROGMEM.
This frees around 1.2KB of heap for any SSL applications.
Also delete unneeded objects from the bearssl.a library to shrink the
GIT repo size.
6bfb1bae40