feat: Support ClickHouse

[ObservedObserver]

Feats:

1. fetch meta data / dataSource from clickhouse.
2. use clickhouse for OLAP (cube) computation.

todo:

1. SQL (or limit SQL) API for OLAP computation tasks. (In visual-insights engine)
2. connectors (proxy cases)
3. meta data transform. (In Rath)
4. data parser (query result -> json) (In Rath / VI)

[todo]

import aggregators list from cube-core

Rath/packages/frontend/src/components/vizPreference.tsx

Lines 14 to 19 in 994fe2f

	// todo: import aggregators list from cube-core
	const aggregationList: Array<{ key: Aggregator; text: string }> = [
	{ key: "sum", text: "Sum" },
	{ key: "count", text: "Count" },
	{ key: "mean", text: "Mean" },
	];

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This comment was generated by todo based on a todo comment in 994fe2f in #71. cc @Kanaries.

[todo]

FIX this in visual insights

Rath/packages/frontend/src/workers/engine/core.ts

Lines 39 to 44 in 994fe2f

	// @ts-ignore TODO: FIX this in visual insights
	const { cube, fieldDictonary } = context;
	const { dimensions, measures } = viewSpace;
	const cuboid = cube.getCuboid(viewSpace.dimensions);
	const aggData = cuboid.getState(measures, measures.map(() => 'sum'));
	const insightSpaces: IInsightSpace[] = []

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This comment was generated by todo based on a TODO comment in 994fe2f in #71. cc @Kanaries.