Minor typos and small additions

[fjukstad]

Summary:

• Updated Docker build instructions, they are now working.
• Added _type : Composition to composition json example.
• EHR STATUS json is now _type:EHR_STATUS, also moved example to its own json file.
• Create Composition should return HTTP 400 if the supplied ehr_id was invalid, e.g. not a GUID.
• Fixed typo in the ResultSet example.
• Added a HTTP 400 for invalid queries
• Create template should return the created template if the Prefer=representation header is present.