Elliptic curves utilities refactory (#2068)

- Usage the new published
[arkworks-extensions](https://github.com/paritytech/arkworks-extensions)
crates.
  Hooks are internally defined to jump into the proper host functions.
- Conditional compilation of each curve (gated by feature with curve
name)
- Separation in smaller host functions sets, divided by curve (fits
nicely with prev point)