[chain] Add Indexer trait

[patrick-ogrady]

No description provided.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 63.33333% with 33 lines in your changes missing coverage. Please review.

Project coverage is 67.81%. Comparing base (8547a4e) to head (001edc3).
Report is 1 commits behind head on push-read-indexer.

Files with missing lines	Patch %	Lines
chain/src/lib.rs	66.66%	21 Missing ⚠️
chain/src/bin/validator.rs	0.00%	8 Missing ⚠️
chain/src/actors/syncer/actor.rs	77.77%	4 Missing ⚠️

@@                  Coverage Diff                  @@
##           push-read-indexer       #5      +/-   ##
=====================================================
+ Coverage              66.35%   67.81%   +1.45%     
=====================================================
  Files                     21       21              
  Lines                   3023     3082      +59     
=====================================================
+ Hits                    2006     2090      +84     
+ Misses                  1017      992      -25     

Files with missing lines	Coverage Δ
chain/src/engine.rs	96.89% <100.00%> (ø)
chain/src/actors/syncer/actor.rs	88.70% <77.77%> (+6.31%)	⬆️
chain/src/bin/validator.rs	0.00% <0.00%> (ø)
chain/src/lib.rs	93.41% <66.66%> (-3.23%)	⬇️

... and 1 file with indirect coverage changes

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