Support for version-less `/openeo/` root?

[soxofaan]

https://github.com/Open-EO/openeo-python-driver/blob/39dfaa415d42fb014bedc84a7a935cb817bca09d/openeo_driver/views.py#L241-L242

This version-less endpoint root /openeo/ is an undocumented unofficial endpoint. We probably had that in the beginning before the API was versioned, or the version discovery mechanism through /.well-known/openeo was settled on.

What to do with this?

• make it "official" by listing it under /.well-known/openeo, where we can make explicit which version it assumes
• remove it

[soxofaan]

according to kibana logs it still seems to be used, so we probably can not just remove it

[soxofaan]

Related and probably an issue here: #40 /.well-known/openeo must not list multiple endpoints with same version, so that might undermine making version-less endpoint root /openeo/ a "blessed" option