Disable sdl comments in executable schema

[kailyak]

Pull Request type

• [ ] Bugfix
• [x] Feature
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] Other (please describe):

Changes in this PR

Added configuration option to toggle showing graphql SDL comments in introspection query results. This feature is only on spring-graphql version of dgs-framework.

By default, SDL comments are shown but are configurable in SchemaOptions.

Descriptions: https://spec.graphql.org/June2018/#sec-Descriptions SDL Comments: https://spec.graphql.org/June2018/#sec-Comments

Config option: dgs.graphql.introspection.show-sdl-comments: Boolean

Issue # 1031

Testing Done

Manual testing on dgs-spring-graphql sample app via toggling feature and running introspection query, added code tests.