feat: add excel tools

[g-linville]

This adds a set of six Excel tool to work with spreadsheet files in the user's OneDrive.
The API refers to a spreadsheet file as a workbook, and a spreadsheet within the workbook (one of the tabs at the bottom of the screen) as a worksheet. I stuck with that naming in this code and in the tool. The LLM doesn't seem confused about it.

[drpebcak]

I know we don't want to nest these too far, but I wonder if it might be time to drop these under a 'microsoft365' folder or something like that, to make it clear that these tools for excel, outlook, etc are for the m365 versions.

[StrongMonkey]

I know we don't want to nest these too far, but I wonder if it might be time to drop these under a 'microsoft365' folder or something like that, to make it clear that these tools for excel, outlook, etc are for the m365 versions.

Good point, or something like o365-excel.

[g-linville]

I think a reorganization of the folders should be discussed with the team. For now, I'm going to merge this.