CD workflow for uploading Entities

[CasperWA]

Closes #4

Add a new CI/CD workflow that will run on all pull requests and pushes to main. It will gather all changed entities and validate them. If it is run as a result of a push to the main branch, it will also, subsequently, upload the entities to onto-ns.com.

A valid entity means it matches the (pydantic) model from entities-service as well as not being different from an existing entity on onto-ns.com, while retaining the same URI.

To do:

• [x] Update entities-service upload command with a --no-summary option or a similar --no-final-confirmation option? Issue: SINTEF/entities-service#119 PR: SINTEF/entities-service#121
• [x] Add the entities-service validate command or similar. Issue: SINTEF/entities-service#118 PR: SINTEF/entities-service#120
• [x] Make the usage of entities-service dynamic with respect to actually changed/added Entities. This has been done, sort of, but a new way of providing inputs is needed. PR: SINTEF/entities-service#126
• [x] Support piping in the sources. Issue: SINTEF/entities-service#130 PR: SINTEF/entities-service#131
• [x] Add a --strict option to validate (and upload) to ensure not changes will be done automagically. Issue: SINTEF/entities-service#129 PR: SINTEF/entities-service#132