perf: fast path operations for small non-native values

[ivokub]

Description

This PR enforces small non-native values to work on zero or one limb. I also added some fast-path operations when we can deduce the result without needing to perform any operations (mul by zero for example).

Also adds a few more emulation parameters useful for implementing small-fields.

Type of change

• New feature (non-breaking change which adds functionality)

How has this been tested?

Existing tests succeed

How has this been benchmarked?

Updated the stats.

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I did not modify files generated from templates
• golangci-lint does not output errors locally
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules