[Design] Error model

[mratsim]

Error model is still to be decided.

Currently asserts are used https://github.com/numforge/laser/blob/be3326bca5d9096e912530c6ed946bb89ee01b6f/laser/strided_iteration/map_foreach.nim#L106-L110

Literature:

• http://joeduffyblog.com/2016/02/07/the-error-model/
• https://github.com/status-im/nimbus/wiki/Exceptions-and-errors
• https://gist.github.com/zah/d2d729b39d95a1dfedf8183ca35043b3

Challenges:

• should the interface exposed be left to higher-level lib? (i.e. leave only asserts as those are removed on release builds)
• If not:
  • Distinguish between recoverable and unrecoverable errors (bugs).
  • For embedded devices recoverable errors "API" must be documented, whether error code or exceptions are chosen.
• Macros like forEach cannot use error codes, high level wrapper should take care of that