Develop ability to maintain a transaction log database

[jordanpadams]

See https://github.com/NASA-PDS/pds-doi-service/blob/master/docs/design/pds-doi-service-srd.md#listretrieve-a-doi for details

[tloubrieu-jpl]

We need a dictionary to match steward ids (e.g. img) with the long name node (e.g Cartography and Imaging Sciences Discipline).

The argument of the command line with be steward id.
The directory name of the transaction archive with also be the steward id.
The value in the DOI record is the long name as for now.

The format of the datetime directory is iso8601, for example: '2020-05-27T14:26:03.140082'
This can be done with python code: datetime.now().isoformat() (use GMT time zone)

Inside each directory we will have 2 files:

• input.. The file is always named input with an extension depending on its type. When the input is URL, the content is saved locally
• output.xml