Test replacing PyFPDF2 by fpdf2 in Odoo

[Lucas-C]

Currently, the open-source project Odoo uses PyPDF2 to render PDFs:

• https://github.com/odoo/odoo/blob/master/setup.py#L50
• https://github.com/odoo/odoo/blob/master/odoo/tools/pdf.py#L19

It would be really interesting to see if fpdf2 could be used as an alternative PDF renderer.

To close this GitHub issue, we could add a section in our documentation, for example on the page Usage in web APIs, describing how to "plug" fpdf2 into Odoo, ideally using a plug-and-play approaching like a module, or else making a fork of https://github.com/odoo/odoo.