Feature/393 schemavalidering

[fredriknordlander]

Pull Request Description

Please include a summary of the change and which issue is fixed or added.
Please also include relevant motivation and context.
List any dependencies that are required for this change.

Fixes #(issue)

Checklist

• Changes are limited to a single goal (avoid scope creep)
• I confirm that I have read any Contribution and Development guidelines (CONTRIBUTING and DEVELOPMENT) and are following their suggestions.
• I confirm that I wrote and/or have the right to submit the contents of my Pull Request, by agreeing to the Developer Certificate of Origin, (adding a 'sign-off' to my commits).

[mmjohansson]

Har börjat kolla på koden, men det är även ett par checks som failar.

1. Följande filer behöver en license header:

• src/util/RapLPIssueHelpers.ts
• src/util/RapLPSpecParseError.ts
• src/util/prettifyOpenAPIErrors.ts
• tests/unit/integration/validateRunner.mjs
• tests/unit/issueHelper.test.ts
• tests/unit/parseApiSpecInput.integration.test.ts

2. Två commits börjar med verb utan imperativ form ("added" borde vara "add"):

• feat: added logic for structural and semantic parsing
• fix: added unit tests for structural and semantic parsing