[FW][IMP] developer: add an article to explain error handling in JS

[fw-bot]

Forward-Port-Of: odoo/documentation#9240

[robodoo]

Pull request status dashboard.

[fw-bot]

This PR targets saas-17.1 and is part of the forward-port chain. Further PRs will be created up to master.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port