use rust types for slots, SubEpochSummary and SubEpochData

[arvidn]

These commits are best reviewed one at a time.

Purpose:

This PR is another part of the long-term effort of transitioning FullBlock to the rust type. This improves serialization/deserialization speed as well as allow more of the validation to live entirely on the rust side.

Some of the performance issues are highlighted here.

This PR is especially targeting serializing and deserializing of SubEpochChallengeSegments.

This PR transitions the following types to rust:

• ChallengeBlockInfo
• ChallengeChainSubSlot
• InfusedChallengeChainSubSlot
• RewardChainSubSlot
• SubSlotProofs
• SubEpochSummary
• EndOfSubSlotBundle
• SubEpochData
• SubEpochChallengeSegment
• SubEpochSegments
• SubSlotData

The rust definition of these types can be found here, here, here and here.

As with earlier types being moved to rust, the integer types are exposed as plain int to python, even though the underlying types are fixed width. This allows mypy to highlight all the places where fields need to be "cast" (or really, where our fixed-width integer type needs to be constructed).

A utility function on StructStream (the base class for our fixed-width integers) was added in the previous PR, construct_optional() which essentially casts an Optional[int] -> Optional[<StructStream>]. This is used for optional members of the rust types, which are exposed as Optional[int] even though the underlying value is restricted by the width of the field.

Since native types implemented in rust cannot (at least to my knowlege) be dataclasses, the free function dataclasses.replace() has to be replaced by a member function replace(), which our rust classes implement.

Current Behavior:

Serializing weight proof messages and deserializing SubEpochChallengeSegments is slow and may block other (more time critical tasks).

New Behavior:

Serializing weight proof messages and deserializing SubEpochChallengeSegments is fast.

[coveralls-official]

Pull Request Test Coverage Report for Build 7489697254

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• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 90.496%

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Totals
Change from base Build 7481196968:	-0.1%
Covered Lines:	94420
Relevant Lines:	104290

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💛 - Coveralls

[github-actions]

File	Coverage	Missing Lines
chia/full_node/full_node_api.py	0.0%	lines 883, 885
chia/timelord/timelord_state.py	0.0%	lines 90, 93-94

Total	Missing	Coverage
52 lines	5 lines	90%