Refactor the interval-api to make it more organized

[clarenceli-msft]

AB#5031

Please refer to the description in #16138, the content is exact the same except for some breaking changes (which will be committed to next). It includes a changeset as well.

[msfluid-bot]

⯆ @fluid-example/bundle-size-tests: -154 Bytes

Metric Name	Baseline Size	Compare Size	Size Diff
aqueduct.js	457.7 KB	457.62 KB	⯆ -77 Bytes
connectionState.js	680 Bytes	680 Bytes	■ No change
containerRuntime.js	246.87 KB	246.87 KB	■ No change
loader.js	151.5 KB	151.5 KB	■ No change
map.js	48.01 KB	48.01 KB	■ No change
matrix.js	148.6 KB	148.6 KB	■ No change
odspDriver.js	94.4 KB	94.4 KB	■ No change
odspPrefetchSnapshot.js	44.87 KB	44.87 KB	■ No change
sharedString.js	165.72 KB	165.65 KB	⯆ -77 Bytes
sharedTree2.js	244 KB	244 KB	■ No change
Total Size	1.72 MB	1.72 MB	⯆ -154 Bytes

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Baseline commit: 42d80cd

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