feat: add safe comparators templates

[0xjei]

Description

This PR adds the safe comparators (SafeLessThan, SafeLessEqThan, SafeGreaterThan, SafeGreaterEqThan) circom templates. These circuits are pretty much similar to the circomlib ones but they add a conversion of the inputs to compare to their bit representations to ensure they fit within 'n' bits (implicit range check).

Compared to the original version of MACI, Anonymous Components were used, resulting in DX improvement and small optimisation.

Related Issue(s)

see #131

Other information

Checklist

• My code follows the style guidelines of this project
• 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
• My changes generate no new warnings
• I have run yarn prettier and yarn lint without getting any errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[ctrlc03]

Good stuff!!
Just added a style suggestion (comments over variables vs side-by-side) and to optionally add some more tests to ensure all cases are covered. Other than that, LGTM

[ctrlc03]

Thanks for adding more tests, great stuff