refactor: move fns as default implementation in EpochManagerAdapter trait

[stedfn]

The PR makes some functions as default implementation in the EpochManagerAdapter trait and deletes unused functions like copy_epoch_info_as_of_block and get_all_block_approvers_ordered

[codecov]

Codecov Report

Attention: Patch coverage is 59.75610% with 33 lines in your changes missing coverage. Please review.

Project coverage is 70.40%. Comparing base (72999fa) to head (60d0950).
Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
chain/epoch-manager/src/adapter.rs	66.19%	7 Missing and 17 partials ⚠️
chain/chain/src/test_utils/kv_runtime.rs	0.00%	6 Missing ⚠️
chain/chain/src/runtime/mod.rs	0.00%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #12853      +/-   ##
==========================================
+ Coverage   70.39%   70.40%   +0.01%     
==========================================
  Files         851      851              
  Lines      174188   174105      -83     
  Branches   174188   174105      -83     
==========================================
- Hits       122614   122579      -35     
+ Misses      46327    46282      -45     
+ Partials     5247     5244       -3     

Flag	Coverage Δ
backward-compatibility	0.16% <0.00%> (+<0.01%)	⬆️
db-migration	0.16% <0.00%> (+<0.01%)	⬆️
genesis-check	1.41% <0.00%> (+<0.01%)	⬆️
linux	70.08% <59.75%> (+0.01%)	⬆️
linux-nightly	70.04% <59.75%> (+0.01%)	⬆️
pytests	1.71% <0.00%> (+<0.01%)	⬆️
sanity-checks	1.53% <0.00%> (+<0.01%)	⬆️
unittests	70.23% <59.75%> (+0.01%)	⬆️
upgradability	0.20% <0.00%> (+<0.01%)	⬆️

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[pugachAG]

why do want to inline it as part of EpochManagerHandle?

[stedfn]

no good reason. reverted with a minor modification