Add command to the CLI to validate the collection metadata file

[Ndpnt]

As example, for this metadata file:

id: demo
name: Demo
tagline: 13
description: |
  The **Demo** collection tracks changes to the terms of use of services used by Open Terms Archive.
  
  This provides a reference collection for best practices and enables the Open Terms Archive Core Team to be a user of the software it produces.
dataset: https://github.com/OpenTermsArchive/demo-versions/releases
declarations: https://github.com/OpenTermsArchive/demo-declarations
versions: https://github.com/OpenTermsArchive/demo-versions
snapshots: https://github.com/OpenTermsArchive/demo-snapshots
donations: https://opencollective.com/opentermsarchive
logo: https://opentermsarchive.org/images/collections/demo.png
languages: [EN]
extraPropsAtRoot: unwanted
jurisdictions: [US-CA]
trackingPeriods:
  - startDate: 2023-01-01
    schedule: "30 */1s2 * * *"
    serverLocation: Roubaix, FR
    extraProps: unwanted
governance:
  Ministry for Europe and Foreign Affairs:
    url: www.diplomatie.gouv.fr
    logo: https://opentermsarchive.org/images/contributors/meae.png
    roles: [host, sponsor]
  Open Terms Archive:
    url: https://opentermsarchive.org
    logo: https://opentermsarchive.org/images/logo/logo-open-terms-archive-black.png
    roles: [administrator, unknown-role, maintainer]

The command returns this output:

↳ npm run metadata:validate

> @opentermsarchive/engine@4.0.2 metadata:validate
> node bin/ota.js validate metadata



  Metadata file validation
    1) is valid


  0 passing (66ms)
  1 failing

  1) Metadata file validation
       is valid:
     Error:
- /root: Found unexpected property "extraPropsAtRoot"
- /tagline: "13" must be string
- /languages/0: "EN" must be a valid ISO 639-1 language code (two lowercase letters, e.g., "en", "fr")
- /trackingPeriods/0: Found unexpected property "extraProps"
- /trackingPeriods/0/schedule: "30 */1s2 * * *" must be a valid cron expression (see https://en.wikipedia.org/wiki/Cron#Cron_expression)
- /governance/Ministry for Europe and Foreign Affairs/url: "www.diplomatie.gouv.fr" must match format "uri"
- /governance/Open Terms Archive/roles/1: "unknown-role" must be equal to one of the allowed values "host", "administrator", "curator", "maintainer", "sponsor"
      at Context.<anonymous> (file:///Users/ndpnt/Workspace/OTA/engine/scripts/metadata/index.mocha.js:83:11)
      at process.processImmediate (node:internal/timers:478:21)

[clementbiron]

The line number #L198 referred to here does not agree with the version of Mocha used and there is no guarantee that this link will work over time.