devtools: Add block hash lookups

[str4d]

Curently doesn't work because lightwalletd does not have support for looking up blocks by hash.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 18 lines in your changes missing coverage. Please review.

Project coverage is 60.51%. Comparing base (8640923) to head (1c71264). Report is 603 commits behind head on main.

Files with missing lines	Patch %	Lines
devtools/src/bin/inspect/main.rs	0.00%	8 Missing :warning:
devtools/src/bin/inspect/lookup.rs	0.00%	6 Missing :warning:
devtools/src/bin/inspect/block.rs	0.00%	4 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1457      +/-   ##
==========================================
- Coverage   60.57%   60.51%   -0.07%     
==========================================
  Files         139      139              
  Lines       16362    16379      +17     
==========================================
  Hits         9911     9911              
- Misses       6451     6468      +17     

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[str4d]

Moved to https://github.com/zcash/zcash-devtool/pull/80.