math.matrices: fix/rename mnorm, update all norms

math.matrices: fix/rename mnorm, update all norms

closes #2244

- `mnorm` has been renamed to `normalize-matrix`
	to reflect what it actually does, which
	is normalize a matrix, not find a norm
	of a matrix.

- `mnorm` is no longer a word defined here.

- bugfix: previously, `normalize-matrix` found
	the supremum of a matrix (`mmax`),
	before taking the supremum's absolute
	value (`abs`) and dividing the matrix
	by it (`m/n`).
	for matrices containing only negative
	values and 0, the supremum is 0, and
	a `div-by-zero` error was thrown.

	`normalize-matrix` has been fixed to
	first `abs` all the matrix elements,
	and then find the supremum and divide,

	it also receieved a zero-matrix? guard
	for optimization and preventing
	`div-by-zero`.

- new alias: `hilbert-schmidt-norm` for
	`frobenius-norm`,  to go along with
	`math.matrices.extras.<hilbert-matrix>`
	and improve searchability by physicists.

- new word: `matrix-p-norm`, written as an
	analogue of `math.vectors.p-norm`.

- new word: `matrix-p-q-norm`, which generalizes
	entrywise matrix norm over the L^p,q
	vector space.

- new word: `matrix-p-norm-entrywise`:
	`matrix-p-norm`'s fallback
	for p =/= 1, 2, inf; analogue of
	`math.vectors.p-norm-default`.

- all norm words have gotten new docs,
	`zero-matrix?` guards as an optimisation,
	and most have gotten new tests.