Improve performance of computing columns of matrices over GF(2)

[GiacomoPope]

In response to issue #38150 I have adjusted the request for columns over dense matrices over GF(2) by replacing the standard call to columns with a transpose followed by a request of rows.

This results in almost a 1000x speed up for large matrices (for the example in the issue).

Old Implementation

sage: M2 = random_matrix(GF(2), 2, 2)
sage: %time _  = M2.columns()
CPU times: user 4.14 ms, sys: 1.67 ms, total: 5.81 ms
Wall time: 10.9 ms
sage: %time _  = M2.rows()
CPU times: user 109 µs, sys: 130 µs, total: 239 µs
Wall time: 1.39 ms
sage: M2 = random_matrix(GF(2), 200, 200)
sage: %time _  = M2.columns()
CPU times: user 87.9 ms, sys: 1.32 ms, total: 89.2 ms
Wall time: 88.3 ms
sage: %time _  = M2.rows()
CPU times: user 811 µs, sys: 96 µs, total: 907 µs
Wall time: 912 µs
sage: M2 = random_matrix(GF(2), 2000, 2000)
sage: %time _  = M2.columns()
CPU times: user 7.94 s, sys: 9.11 ms, total: 7.95 s
Wall time: 7.97 s
sage: %time _  = M2.rows()
CPU times: user 7.49 ms, sys: 770 µs, total: 8.26 ms
Wall time: 7.97 ms

New Implementation

sage: M2 = random_matrix(GF(2), 2, 2)
sage: %time _  = M2.columns()
CPU times: user 1.01 ms, sys: 261 µs, total: 1.27 ms
Wall time: 3.75 ms
sage: %time _  = M2.rows()
CPU times: user 54 µs, sys: 8 µs, total: 62 µs
Wall time: 65.1 µs
sage: M2 = random_matrix(GF(2), 200, 200)
sage: %time _  = M2.columns()
CPU times: user 1.09 ms, sys: 40 µs, total: 1.13 ms
Wall time: 1.13 ms
sage: %time _  = M2.rows()
CPU times: user 712 µs, sys: 15 µs, total: 727 µs
Wall time: 732 µs
sage: M2 = random_matrix(GF(2), 2000, 2000)
sage: %time _  = M2.columns()
CPU times: user 9.07 ms, sys: 746 µs, total: 9.82 ms
Wall time: 9.54 ms
sage: %time _  = M2.rows()
CPU times: user 7.82 ms, sys: 687 µs, total: 8.51 ms
Wall time: 8.18 ms

Fixes #38150

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[grhkm21]

Just small style changes, then it should be good. Thanks for the easy but much needed improvement!

[GiacomoPope]

Thanks for the tips -- I was lazy and copy pasted old columns code, so these changes could be applied elsewhere too but that's for another day!

[grhkm21]

good enough. I think the entire file can be refactored later lol

[GiacomoPope]

Haha yeah one problem at a time I guess