Expose isEqual options to the user

[hasparus]

See #165 (comment).

Currently, the options documented in https://earljs.dev/docs/advanced/equality-algorithm#algorithm are not exposed to the user. While I personally wouldn't set uniqueNaNs or minusZero to true, some advanced Earl users might need it, especially when migrating from other assertion libraries.

[sz-piotr]

Closing this as this is not in scope for the foreseeable future. The options are available if the user wishes to call toEqual directly, but otherwise we prefer to keep the matchers simple.