Improve Date Ranges and Time Grouping

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**Is your feature request related to a problem? Please describe.**
It's not very user friendly to figure out how to do date ranges and grouping currently. For example, I want to show the previous 30 days summed and compare to previous year in a bar chart. If I limit my query data to previous 30 days then previous period data will be missing. If I group by month in Time Grouping then its by month instead of previous 30 days, which is different.

The compare to previous period is only available to some charts as well. And it doesn't let you customize which period its comparing to.

**Describe the solution you'd like**
I would like the ability to compare to previous periods without using a time grouping, and for it to be user friendly and intuitive the same as Mixpanel.

Here's how date ranges work in Mixpanel. You have an easy date filter:

You have an easy option to compare to previous periods:

Which then automatically displays the appropriate data like this:

**How important is this feature to you?**
Very important. It made me start considering going back to Mixpanel, even though that is very expensive and I would prefer to stick with a self hosted tool.

If you've never used Mixpanel before, I would suggest giving it a try. They have a free version that is event limited, but you can get a lot of inspiration from them on how to make your date filters and comparisons more intuitive.

No files, tests, or entry points are named. Start by reviewing the existing date-range, time-grouping, and compare-to-previous-period behavior, then define supported comparison periods and clear acceptance criteria using the Mixpanel examples; the work is done when the proposed experience is implemented consistently for the relevant chart types.

Written by the indexing model from the issue text.