Aleksei Zinovev

Make SampleNotebooksTests not ignored and update Notebooks examples

1

Currently, the SampleNotebooksTests have all tests as disabled because of deprecated code and dependencies there Need to revisit all these examples, remove `@Ignore` annotations and make them actual and fresh.

- [ ] number of loaded rows - [ ] total number of rows in the table/query - [ ] number of data/size of data calculated by footprint in memory,...

The existing solution supports only presenting JSON type as a String We need to convert correct JSON strings to the hierarchical structure after reading from the Result Set

The proposed idea adds data/time auto-discovering in the spirit of the CSV integration [the link](https://github.com/Kotlin/dataframe/blob/913d6a0fe0fe2f30573b1f0c7696146457392f39/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/parse.kt#L218) All approaches should be aligned and unified Now we have java.sql.time* types instead of Kotlin

Add functions to read database meta-information to dataframe

1

- [ ] tables - [ ] columns and its types - [ ] number of rows and columns in the table - [ ] number of nulls in columns...

Replace io.File on nio.Path in DataFrame.read methods

2

Now we are using File class from java.io in our API for reading DataFrames instead of Path from java.nio For example ```kotlin public interface SupportedDataFrameFormat : SupportedFormat { public fun...

There are a few empty [pages](https://kotlin.github.io/dataframe/specialcolumntypes.html) that should be filled in.

The [page](https://kotlin.github.io/dataframe/columnstatistics.html) is empty

The [page ](https://kotlin.github.io/dataframe/columnarithmetics.html) is empty

- [ ] Gradle (groovy) for JVM - [ ] Gradle (kts) for JVM - [ ] Android Gradle (groovy) - [ ] Android Gradle (kts) Android could be based...