[WIP] Rewriting the Univariate Solver

This PR aims to rewrite a cleaner and robust univariate equation solver.
- [ ] Univariate
    - [x] polynomial
    - [x] rational
    - [ ] trigonometric
    - [ ] functions with exp and log
- [ ] Multivariate
> Informally any equation in which at least one variable expression is stuck inside a radical.

Do you mean `sin(x)+cos(x+sqrt(x+10))+x`?

Can you be more formal, please?