Generalize block sparse matricize

[mtfishman]

This rewrite block sparse matricize/unmatricize to call matricize/unmatricize blockwise, while before it called out to blockreshape. The previous logic was too limited when the blocks themselves have more structure and we don't want to simply reshape them, for example for Kronecker blocks.

This is breaking because it makes the blocksparse constructor stricter, now you can call blocksparse(d, [2, 3], [2, 3]) or blocksparse(d, blockedrange.(([2, 3], [2, 3]))) but not blocksparse(d, ([2, 3], [2, 3])) or blocksparse(d, blockedrange.(([2, 3], [2, 3]))...). That matches the convention in BlockArrays.jl constructors and avoids ambiguities since an input like blocksparse(d, Base.OneTo(3)) would be ambiguous otherwise (it wouldn't be clear if those should be block lengths or the axis).

[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.37%. Comparing base (229248e) to head (a6efc60).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/BlockArraysExtensions/blockrange.jl	16.66%	5 Missing ⚠️
...rProductsExt/BlockSparseArraysTensorProductsExt.jl	0.00%	3 Missing ⚠️
...stractblocksparsearray/abstractblocksparsearray.jl	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #163      +/-   ##
==========================================
- Coverage   75.95%   75.37%   -0.59%     
==========================================
  Files          36       37       +1     
  Lines        2059     2091      +32     
==========================================
+ Hits         1564     1576      +12     
- Misses        495      515      +20     

Flag	Coverage Δ
docs	7.18% <4.44%> (-0.07%)	⬇️

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