feat(core): add support for adhoc columns

[villebro]

🏆 Enhancements

Add new type AdhocColumn that can be used as a dimension similar to how AdhocMetric can be used as a (non-saved) metric in query requests.

[vercel]

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🔍 Inspect: https://vercel.com/superset/superset-ui/Edr9PDYejhHJY8GBbgrbyAUzsu6X
✅ Preview: https://superset-ui-git-fork-preset-io-hack2021-adhoc-columns-superset.vercel.app

[codecov]

Codecov Report

Merging #1342 (8593fa6) into master (887adbd) will increase coverage by 0.10%.
The diff coverage is 74.41%.

@@            Coverage Diff             @@
##           master    #1342      +/-   ##
==========================================
+ Coverage   30.81%   30.91%   +0.10%     
==========================================
  Files         499      503       +4     
  Lines       10193    10215      +22     
  Branches     1760     1761       +1     
==========================================
+ Hits         3141     3158      +17     
- Misses       6800     6805       +5     
  Partials      252      252              

Impacted Files	Coverage Δ
...ui-chart-controls/src/operators/boxplotOperator.ts	100.00% <ø> (ø)
...t-ui-chart-controls/src/operators/pivotOperator.ts	100.00% <ø> (ø)
...controls/src/operators/timeComparePivotOperator.ts	100.00% <ø> (ø)
...ges/superset-ui-core/src/query/buildQueryObject.ts	100.00% <ø> (ø)
plugins/plugin-chart-echarts/src/BoxPlot/types.ts	0.00% <ø> (ø)
plugins/plugin-chart-echarts/src/Funnel/types.ts	100.00% <ø> (ø)
plugins/plugin-chart-echarts/src/Gauge/types.ts	100.00% <ø> (ø)
.../plugin-chart-echarts/src/MixedTimeseries/types.ts	100.00% <ø> (ø)
plugins/plugin-chart-echarts/src/Pie/types.ts	100.00% <ø> (ø)
...s/plugin-chart-echarts/src/Radar/transformProps.ts	0.00% <0.00%> (ø)
... and 21 more

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[kgabryje]

That looks great, can't wait to see the whole feature working!

[junlincc]

@villebro it sounds great, can you add a video to demo the. change though?