Contribution of Synthetic Data Use Cases, Requirements & Language and Terminology from #30

[mcleo-d]

Note : This pull request replaces #39 and should be merged after #43 is approved and merged.

Description

This PR combines and reformats the User Cases, Requirements and Language and Terminology contributions as markdown made by @andrewcarrblue and @BenFielding in the comments of #30

• @andrewcarrblue - https://github.com/finos/datahub/issues/30#issuecomment-664355125
• @andrewcarrblue - https://github.com/finos/datahub/issues/30#issuecomment-651734549
• @BenFielding - https://github.com/finos/datahub/issues/30#issuecomment-667943969

Contributed Folder Structure

|__ docs
    |__ synthetic-data-roadmap
        |__ language-and-terminology.md
        |__ use-cases-and-requirements.md

Additional Information

This PR does not close #30 as there are addition tasks mapped out in the issue for taking prioritised stories into development.

[mcleo-d]

Hi @grovesy,

I merged this change on your behalf. Thanks for approving 👍

James.