implement higher_order, components via sparse.matrix

[martinfleis]

Clearing up some to-do's in the graph stuff. higher_order and components (n_components, component_labels) stuff is not yet supported in scipy on sparse arrays so going temporarily via sparse matrix.

I also fixed conversion from sparse when islands are present as I bumped into that in higher_order.

[codecov]

Codecov Report

Merging #577 (787de3d) into main (9682163) will increase coverage by 0.1%.
The diff coverage is 100.0%.

@@           Coverage Diff           @@
##            main    #577     +/-   ##
=======================================
+ Coverage   82.3%   82.5%   +0.1%     
=======================================
  Files        129     129             
  Lines      15318   15358     +40     
=======================================
+ Hits       12611   12664     +53     
+ Misses      2707    2694     -13     

Files	Coverage Δ
libpysal/graph/_utils.py	88.3% <100.0%> (+0.1%)	⬆️
libpysal/graph/base.py	96.4% <100.0%> (+1.9%)	⬆️
libpysal/graph/tests/test_base.py	100.0% <100.0%> (ø)

... and 1 file with indirect coverage changes