Enhancement: WorkbookContextFactory - SXSSFWorkbook

[ruibritopt]

Expand the possibilities in the WorkbookContextFactory to include SXSSFWorkbook.
Switch...Case and ENUM could solve the decision process.
SXSSFWorkbook provides faster writing speeds, especially for larger documents.
For that reason, I believe this to be a good enhancement to this library.

[serddmitry]

Feel free to submit a pull request.