Docs: Basics docs refactor (#56905)

* renames directory

* fixes relrefs

docs/sources/developers/plugins/data-frames.md

@@ -74,7 +74,7 @@ A data transformation is any function that accepts a data frame as input, and re
 
 A data frame with at least one time field is considered a _time series_.
 
-For more information on time series, refer to our [Introduction to time series]({{< relref "../../basics/timeseries/" >}}).
+For more information on time series, refer to our [Introduction to time series]({{< relref "../../fundamentals/timeseries/" >}}).
 
 ### Wide format