implement getProof and verifyProof on trie

[rianhughes]

closes: #1851

[codecov]

Codecov Report

Attention: Patch coverage is 82.30769% with 23 lines in your changes are missing coverage. Please review.

Project coverage is 75.35%. Comparing base (576d342) to head (a07d3d5).

Files	Patch %	Lines
core/trie/proof.go	82.24%	10 Missing and 9 partials ⚠️
core/trie/key.go	80.95%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1852      +/-   ##
==========================================
+ Coverage   75.22%   75.35%   +0.12%     
==========================================
  Files          96       97       +1     
  Lines        8183     8313     +130     
==========================================
+ Hits         6156     6264     +108     
- Misses       1506     1517      +11     
- Partials      521      532      +11     

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[asdacap]

Aside from the proving need to work for range also instead of just one leaf (can be done later), looks good to me.