Create an track collection metadata section with optional trackhub name and id

[Sveinung Gundersen]

Should go into the top-level schema. Will represent the "investigation" level of the ISA model, while Study=study and Assay=experiment

[Sveinung Gundersen]

@dzerbino @jmfernandez This should probably have been a pull request, as it adds quite a bit of additional fields, but I forgot about it in the hurry. Please review the commit for details and comment here (and possible reopen).

[José María Fernández]

There are some issues in the generated JSON Schema, as you can see in description_url declaration:

fairtracks_standard/json/schema/fairtracks.schema.json

Lines 48 to 71 in 0b1a3ad

 "description_url": { 
     "description": "URL to a web page or file describing the track collection", 
     "type": "string", 
     "format": "url", 
     "properties": { 
         "source_repo": { 
             "type": "object", 
             "properties": { 
                 "repo_url": { 
                     "description": "URL to the track repository containing the collection (e.g., the Track Hub Registry)", 
                     "type": "string", 
                     "format": "url" 
                 }, 
                 "local_id": { 
                     "description": "Submitter-local identifier (within track repository) for the collection", 
                     "type": "string" 
                 } 
             }, 
             "required": [ 
                 "repo_url" 
             ] 
         } 
     } 
 },