Feature request: Reduced Row Echelon Form

[turonn]

Reduced Row Ecehelon form is a common linear algebra expression that I was surprised was not included in the Matrix gem already. I came upon the need for it while solving today's Advent of Code problem.

Proposed use:

matrix = Matrix[
  [94, 22, 8400],
  [34, 67, 5400]
]

matrix.rref # =>
[ 
  [1, 0, 80],
  [0, 1, 40]
]

Edge cases:

• Infinite/multiple solutions
• No solution
• Invalid Matrixes containing non-numbers

Before we put in the efforts to add this instance method, I'm wondering if this is something worth adding and how we would want to handle the outputs of the edge cases.