Improve hictk zoomify

[robomics]

Update hictk zoomify to support --nice-steps and --pow2-steps options.

[codecov]

Codecov Report

Merging #66 (060e2c8) into main (cac5aa5) will decrease coverage by 0.08%.
Report is 2 commits behind head on main.
The diff coverage is 68.96%.

❗ Current head 060e2c8 differs from pull request most recent head 4776823. Consider uploading reports for the commit 4776823 to get more accurate results

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
- Coverage   82.56%   82.49%   -0.08%     
==========================================
  Files          81       81              
  Lines        5674     5700      +26     
==========================================
+ Hits         4685     4702      +17     
- Misses        989      998       +9     

Files	Coverage Δ
src/hictk/cli/cli_dump.cpp	84.81% <100.00%> (ø)
src/hictk/cli/cli_zoomify.cpp	75.78% <67.85%> (-3.93%)	⬇️