[ADD]report_xlsx_boilerplate

New addon to have the possibility to add Excel boilerplate templates. This can be useful for those reports where we want to always have a predetermined structure in which we then want to add more information.
Example: we always now that the Column Headers will be: Header 1, Header 2, ... We can add the Boilerplate with the Headers, and from there, in the `generate_xlsx_report` method, we will already have the predefined Excel so that we can edit on top of it.

setup/report_xlsx_boilerplate/odoo/addons/report_xlsx_boilerplate

@@ -0,0 +1 @@
+../../../../report_xlsx_boilerplate

setup/report_xlsx_boilerplate/setup.py

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+import setuptools
+
+setuptools.setup(
+    setup_requires=['setuptools-odoo'],
+    odoo_addon=True,
+)