SIMPL-8554: Add handling of requiredOnFrontendOnly property

Some properties in the schema are required by the sdtooling-be's enrichAndValidate step, but at the same time are not published to the catalogue. These properties can't be marked in the schema as required by marking it minCount 1, because then the catalogue will be looking for it, but it is not actually sent to the catalogue, it's just for EDC registration.

Other changes:

• New favicon
• Header converted to vue (same as catalogue UI)
• Added a test for the ttlParser to check correct handling for the new properties