Merge changes from topic "refactor-arm-key-files" into integration

* changes:
  feat(mbedtls): optimize SHA256 for reduced memory footprint
  refactor(arm): rename ARM_ROTPK_HEADER_LEN
  docs(arm): update docs to reflect rotpk key changes
  feat(arm): use provided algs for (swd/p)rotpk
  feat(arm): use the provided hash alg to hash rotpk