webui: Add timeline for visualizing results count aggregation; replace `Luxon` with `dayjs`.

[junhaoliao]

References

1. #309 integrated reducer server and added support for count aggregations.
2. #331 added support for the time bucketed count aggregation.

Description

1. Add timeline for visualizing results count aggregation.
2. Replace datetime manipulation library Luxon with dayjs.
3. Avoid removing inserted collections in SearchJobCollectionsManager to avoid creating a new Meteor.Mongo.Collection object with a same name.

Validation performed

1. cd <PROJECT_ROOT>; task
2. cd ./build/clp-package/sbin; ./start-clp.sh
3. ./compress.sh ~/samples/hive-24hr/i-00c90a0f/
4. Opened the WebUI address in a browser.
5. Started a query with string 1 and observed the job finished without error.
6. Observed the timeline was displayed in default time range selection, which is from Unix epoch to a year from now.
7. Hovering onto the one-and-only-one column showed a tooltip, which displayed logs count in the time bucket of desired size of 2 years.
8. Dragged to zoom in. Kept zooming in until the time buckets are broken down into reasonable sizes and spanned across the whole timeline. Observed the full starting date time on the left bottom corner of the chart correctly reflected the start of the timeline.
9. Kept zooming in until a single column was visible. Verified the timestamp of the one-and-only-one bucket was matching the ones in the results table.