feat: add 3 bundle file

[hustcc]

• fixed G2 多 bundle 包构建 #5592
• 3 bundle
• 按需构建，包大小优化

• 扩展包

[pearmini]

我觉得如果入口文件都放在 src 里面会存在一些问题：

首先让人看上去有点疑惑，为啥这么多入口问题；其次这些文件只是给 UMD 用，严格来讲不是 src 的一部分。感觉更清晰的做法是额外有一个文件夹放这些入口文件？

• bundle
  • g2.index.ts
  • g2-lite.index.ts
  • g2-full.index.ts
  • g2-runtime.index.ts
  • g2-plot.index.ts
• src
  • index.ts

这样保证整个 src 下面的结构更清晰。我发现 observable/plot 也有相似的结构。

[coveralls]

Pull Request Test Coverage Report for Build 6310723675

• 30 of 30 (100.0%) changed or added relevant lines in 5 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.01%) to 88.182%

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Files with Coverage Reduction	New Missed Lines	%
src/composition/repeatMatrix.ts	1	91.89%

Totals
Change from base Build 6297639807:	-0.01%
Covered Lines:	10000
Relevant Lines:	10982

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💛 - Coveralls