Add comments to Prisma Schema and GraphQL server (#162)

* Lowercase all relations in prisma/graphql schema

* Add Comments data model and graphql schema

* Make comments availalble on the api through resolvers and guard them

* Update front graphql schema

* Fix PR

server/src/api/@generated/comment-thread-target/comment-thread-target-where-unique.input.ts

@@ -0,0 +1,8 @@
+import { Field } from '@nestjs/graphql';
+import { InputType } from '@nestjs/graphql';
+
+@InputType()
+export class CommentThreadTargetWhereUniqueInput {
+  @Field(() => String, { nullable: true })
+  id?: string;
+}