Add pictures for RANGE QUERY docs

[tisonkun]

It's unintuitive to understanding all the parameters of RANGE QUERY meaning.

I'd suggest we use some pictures like:

• https://learn.microsoft.com/en-us/azure/stream-analytics/stream-analytics-window-functions
• https://zhuanlan.zhihu.com/p/103890281

to demonstrate how to write RANGE QUERY.

What do you think? @nicecui @waynexia @Taylor-lagrange

[tisonkun]

But it seems we actually don't have complex window. Instead, we use always tumbling window.

The ALIGN parameter only affect the timestamp of result rows?

UPDATE: No. RANGE is the window size and ALIGN is the step, so we still have multiple kinds of windows.

[Taylor-lagrange]

https://docs.greptime.com/user-guide/query-data/sql#time-range-window

We indeed have some picture to explain how Range query works

[tisonkun]

@Taylor-lagrange Cool. I hit this page (https://docs.greptime.com/reference/sql/range#range-query) and perhaps it needs some cross links.