Google now requires an API key for the static maps API.
As API calls cost money, and we cannot restrict the domain of the caller
with the API key in emails, as the domain may vary vastly,
the signing of static API URLs is implemented in the existing
'google_map_img' of partners.
This in turn can be used to get a url for an existing location.
While preventing anyone from stealing the API key for their own purposes
task - 3079113
Part-of: odoo/odoo#107200
Renaud Thiry
83e4551492