Fix ods w3.org namespace

[csarven]

The current namespace of ods is stated as https://www.w3.org/ods/ however - to the best of my knowledge - W3C will not allocate anything top level as such. Namespaces are typically available from http://www.w3.org/ns/. So http://www.w3.org/ns/ods/ may be possible. Please confirm with W3C staff / Team contacts and/or chairs of a W3C Group or W3C CG/BG (e.g., W3C ODRL CG) or other body in which ODS may be proposed through.

See also:

• https://www.w3.org/2005/07/13-nsuri
• w3.org/ns/ development and management policy w3c/ns#2
• https://www.w3.org/2016/08/namespaces/