Remove babel

[dapplion]

Motivation

Through multiple tsc version it has been shown that babel does not add any performance increase in code compilation. Lodestar is not distributed directly to the browser, but only to NodeJS. We should only ensure compatibility with NodeJS v12.9.0. Browser compatibility should be ensured by Lodestar consumers, such as the Lightclient demo UI, which has babel and transpiles the code there.

See "StackOverflow Why do I need Babel JS?" https://stackoverflow.com/questions/39401836/why-do-i-need-babel-js

Description

Compile code with Typescript aiming at doing the least transformations possible to ensure high performance of direct NodeJS consumers.

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PS: Sometimes the generated code by transpilers to support CommonJS has shown up in profilers, indicating it has a performance cost. We should:

• Investigate which features are left out when transpiling to es2019, and their performance cost
• Investigate the cost of CommonJS exports vs ES6 exports. In this branch I'm testing how feasible it is to switch https://github.com/ChainSafe/lodestar/tree/dapplion/esnext

[codeclimate]

Code Climate has analyzed commit 011ef7d and detected 0 issues on this pull request.

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[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for some benchmarks.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold.

Benchmark suite	Current: 67e71dd	Previous: 05e8265	Ratio
Process block - 250000 vs - 7PWei - with 0 validator exit	9.1636 ms/op	354.94 us/op	25.82
shuffle list - 16384 els	26.493 ms/op	1.5060 ms/op	17.59
shuffle list - 250000 els	364.41 ms/op	21.502 ms/op	16.95

Full benchmark results

Benchmark suite	Current: 67e71dd	Previous: 05e8265	Ratio
getCommitteeAssignments - req 1000 vs - 250000 vc	7.8467 ms/op	7.8467 ms/op	1.00
epoch altair - 250000 vs - 7PWei - processInactivityUpdates	2.5107 s/op	2.2111 s/op	1.14
epoch altair - 250000 vs - 7PWei - processRewardsAndPenalties	1.1006 s/op	883.38 ms/op	1.25
epoch altair - 250000 vs - 7PWei - processParticipationFlagUpdates	470.43 ms/op	353.07 ms/op	1.33
Process block - 250000 vs - 7PWei - with 0 validator exit	9.1636 ms/op	354.94 us/op	25.82
Process block - 250000 vs - 7PWei - with 1 validator exit	89.736 ms/op	32.650 ms/op	2.75
Process block - 250000 vs - 7PWei - with 16 validator exits	29.881 ms/op	26.815 ms/op	1.11
epoch phase0 - 250000 vs - 7PWei - beforeProcessEpoch	1.7145 s/op	634.02 ms/op	2.70
epoch phase0 - 250000 vs - 7PWei - processRewardsAndPenalties	771.82 ms/op	458.47 ms/op	1.68
epoch phase0 - 250000 vs - 7PWei - processEffectiveBalanceUpdates	108.23 ms/op	109.10 ms/op	0.99
getAttestationDeltas - 250000 vs - 7PWei	125.27 ms/op	92.590 ms/op	1.35
processSlots - 250000 vs - 7PWei - 32 empty slots	3.3836 s/op	4.5431 s/op	0.74
shuffle list - 16384 els	26.493 ms/op	1.5060 ms/op	17.59
shuffle list - 250000 els	364.41 ms/op	21.502 ms/op	16.95
getPubkeys - persistent - req 1000 vs - 250000 vc	19.477 us/op	15.169 us/op	1.28
BLS verify - blst-native	2.0859 ms/op	1.6439 ms/op	1.27
BLS verifyMultipleSignatures 3 - blst-native	4.1967 ms/op	3.3547 ms/op	1.25
BLS verifyMultipleSignatures 8 - blst-native	9.1762 ms/op	7.2510 ms/op	1.27
BLS verifyMultipleSignatures 32 - blst-native	34.231 ms/op	28.700 ms/op	1.19
BLS aggregatePubkeys 32 - blst-native	47.597 us/op	35.819 us/op	1.33
BLS aggregatePubkeys 128 - blst-native	184.10 us/op	137.18 us/op	1.34
getAttestationsForBlock	79.267 ms/op	86.567 ms/op	0.92
validate gossip signedAggregateAndProof - struct	5.4607 ms/op	5.3061 ms/op	1.03
validate gossip signedAggregateAndProof - treeBacked	5.3298 ms/op	4.0418 ms/op	1.32
validate gossip attestation - struct	2.4470 ms/op	1.8708 ms/op	1.31
validate gossip attestation - treeBacked	2.5060 ms/op	1.9100 ms/op	1.31

by benchmarkbot/action