refactor: move NightshadeRuntime to chain

[pugachAG]

This PR is a part of getting rid of KeyValueRuntime (#10678) and MockEpochManager (#10634).

Currently NightshadeRuntime is part of nearcore which makes it impossible to use it in chain since chain depends on nearcore. We need to use NightshadeRuntime as a replacement for KeyValueRuntime in chain tests. Ideally it would be great to move it to node-runtime crate, but currently it has a lot of dependencies from near_chain which makes it very challenging, so as the first step let's move it to chain.

This PR includes:

• move nearcore::runtime to near_chain::runtime
• introduce NightshadeRuntimeExt to expose NightshadeRuntime::from_config separately since NearConfig is part of nearcore
• move GenesisExt test methods directly to Genesis, also duplicate some constants for now (will be refactored separately to reduce size of this PR).
• move the necessary migrations code to chain

[codecov]

Codecov Report

Attention: Patch coverage is 95.84775% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 72.26%. Comparing base (7bad46a) to head (731ff7c).

Files	Patch %	Lines
chain/chain/src/runtime/mod.rs	47.82%	11 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #10675      +/-   ##
==========================================
- Coverage   72.28%   72.26%   -0.02%     
==========================================
  Files         732      734       +2     
  Lines      150408   150457      +49     
  Branches   150408   150457      +49     
==========================================
+ Hits       108716   108732      +16     
- Misses      36753    36781      +28     
- Partials     4939     4944       +5     

Flag	Coverage Δ
backward-compatibility	0.24% <0.00%> (-0.01%)	⬇️
db-migration	0.24% <0.00%> (-0.01%)	⬇️
genesis-check	1.40% <0.00%> (-0.01%)	⬇️
integration-tests	36.88% <86.15%> (+<0.01%)	⬆️
linux	71.09% <95.84%> (-0.03%)	⬇️
linux-nightly	71.70% <95.84%> (-0.01%)	⬇️
macos	55.29% <93.42%> (-0.07%)	⬇️
pytests	1.66% <36.39%> (+0.03%)	⬆️
sanity-checks	1.41% <36.39%> (-0.01%)	⬇️
unittests	68.11% <93.42%> (-0.02%)	⬇️
upgradability	0.28% <0.00%> (-0.01%)	⬇️

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[nagisa]

Currently NightshadeRuntime is part of nearcore which makes it impossible to use it in chain since chain depends on nearcore.

Could you please expand on this part? Why is it necessary to make it possible to use it in a chain? There's a leap in the reasoning between this and the goal to get rid of the Mock thingy.

[robin-near]

Wow this is a big refactor. I can't really get through it today because unfortunately a lot of these changes are hard to review because they are moved around, but am I right that the only changes are to move code around and not to do anything else at all?

[pugachAG]

@robin-near yes, this change is purely about moving the code around, nothing else is changed.