8.0 port of report_xls module

I want to create a PR for the OCA 8.0 branch of the reporting engines but this branch doesn't exist yet.
Hence I have selected a PR into master.
Can you someone also create the 8.0 branch and put my 8.0 version of the report_xls module into that branch (or alternatively explain me how to do it myself) ? 

Tx,
Luc