Reduced dependencies within num

[jorgecarleitao]

num is a "metacrate" with 5 crates, but we only use num-traits. This PR migrates from one to the other.

[codecov]

Codecov Report

Merging #353 (a3f1391) into main (87aa617) will decrease coverage by 0.67%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##             main     #353      +/-   ##
==========================================
- Coverage   81.01%   80.33%   -0.68%     
==========================================
  Files         326      326              
  Lines       21172    21275     +103     
==========================================
- Hits        17152    17091      -61     
- Misses       4020     4184     +164     

Impacted Files	Coverage Δ
src/array/dictionary/mod.rs	72.50% <ø> (ø)
src/array/specification.rs	70.00% <ø> (ø)
src/compute/arithmetics/basic/add.rs	94.83% <ø> (ø)
src/compute/arithmetics/basic/div.rs	96.52% <ø> (ø)
src/compute/arithmetics/basic/mul.rs	94.83% <ø> (ø)
src/compute/arithmetics/basic/pow.rs	100.00% <ø> (ø)
src/compute/arithmetics/basic/rem.rs	96.52% <ø> (ø)
src/compute/arithmetics/basic/sub.rs	94.83% <ø> (ø)
src/compute/arithmetics/mod.rs	51.12% <ø> (ø)
src/compute/arithmetics/time.rs	97.48% <ø> (ø)
... and 14 more

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