Update the license fields according to frictionless specifications

[Ludee]

Description of the issue

Latest version has two additional (custom) fields for the license: attribution and instruction.
They are very useful but not conform with frictionless.

The documentation has specific keys for this:

"licenses" : [{
    "name": "CC-BY-4.0",
    "path": "https://creativecommons.org/licenses/by/4.0/",
    "title": "Creative Commons Attribution 4.0"
  }],
  "copyrightNotice": "© The State of Queensland 1995–2017",
  "copyrightStatement": "https://www.qld.gov.au/legal/copyright",
  "attributionText": "Science, Information Technology and Innovation, Queensland Government, Coastal Data System – Near real time wave data, licensed under Creative Commons Attribution 4.0 sourced on 26 December 2017",

Source: https://frictionlessdata.io/blog/2018/03/27/applying-licenses/#provide-additional-license-information

Ideas of solution

• Rename key attribution to copyrightNotice
• Add terms copyrightStatement to a link that proves the data is licensed

Discuss:

• attributionText is not conform with TASL. Would be a copy of other keys depending on the licenses.
• instruction is a nice-to-have feature that briefly states the rights and obligation. Do we keep it?

Workflow checklist

• I am aware of the workflow in CONTRIBUTING.md

[jh-RLI]

As far as I understand, we don't have to use the exact naming from the frictionless example. They used, this specific names as they are proposed by this guide of the open data institute.

In general, we could also keep our naming, as these fields are additional fields that are not part of the frictionless specification.