OpenAPI 3.0.x language server linting rules

[char0n]

The scope of this issue is to provide linting rules in apidom-ls for OpenAPI 3.0.3 specification.

Implementation progress

Only fully implemented specification objects should be checked here.

• OpenAPI Object
• Info Object
• Contact Object
• License Object
• Server Object
• Server Variable Object
• Components
• Paths Object
• Path Item Object
• Operation Object
• External Documentation Object
• Parameter Object
• Request Body Object
• Media Type Object
• Encoding Object
• Responses Object
• Response Object
• Callback Object
• Example Object
• Link Object
• Header Object
• Tag Object
• Reference Object
• Schema Object
• Discriminator Object
• XML Object
• Security Scheme Object
• OAuth Flows Object
• OAuth Flow Object
• Security Requirement Object
• Specification extensions

[char0n]

Schema Object will be handled separately in #2186