New `Expr` operators/functions

[balacij]

• [ ] Vector:

  • [x] #2630
  • [ ] Scaling
  • [ ] Addition

• [ ] Matrix:

  • [ ] Negation
  • [ ] Inversion
  • [ ] Determinant
  • [ ] Scaling
  • [ ] Addition
  • [ ] Generation: "eye", triangle, etc

• [ ] pow variants

  Quite a few languages have a ^ operator for when the base is real and the power is a natural number. Right now, GOOL doesn't as far as I could tell, so that's a deeper problem (make an issue please).

Originally posted by JacquesCarette https://github.com/JacquesCarette/Drasil/pull/2486#pullrequestreview-664937862

[balacij]

We can add these as needed, I suppose. It's not necessarily hard-required. So I'm removing it the scope of my Master's.