Epic: Excel write performance improvements

[AdRiley]

Where we are today at a component level

Java

Enso

Changes we want to make

1. Switch writing a brand new Workbook to use the POI streaming mode - Done Make xlsx use the streaming model for new files #13842
2. Remove dependency of Enso on 3rd party POI libraries - Done Remove poi references from enso code #13953
3. Remove the dependency from Enso onto the ExcelConnectionPool. This becomes an implementation detail of the ExcelReader and ExcelWrite classes. An implication here is that Excel_Workbook no longer needs to hold a reference counted object holding open the Excel file on disk. Remove the dependency from Enso onto the ExcelConnectionPool #13988
4. Add a timestamp to Enso_Workbook of last modified date. If this has changed when we subsequently call read on that object then warn the user.
5. Make writing a new sheet to an existing workbook use the POI streaming mode.
6. Make appending to an existing sheet use the POI streaming mode.