fix: Schema name conflict errors

[calvincestari]

PR 2 of 3 for #2546

This PR ensures that the user-given schema name:

• does not conflict with any of the generated file/type names by disallowing the schema name to match any of the schema referenced types
• does not conflict with any of the generation selection set names by disallowing a schema name matching any entity field name and any pluralized version of an entity list name
• these checks are done during the compilation stage because that is where the code still has access to the schema and can check field definition types
• ValidationRule checks have been reduced to only reserved words

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[AnthonyMDev]

Just a typo and minor addition to the schema conflict error message. But otherwise this LGTM!

[calvincestari]

Just a type and minor addition to the schema conflict error message. But otherwise this LGTM!

Still wanting to add the entity vs. list behaviours to this PR too.

[calvincestari]

Arguably this check could go into the below if (isCompositeType(unwrappedFieldType)) { statement, let me know if you feel strongly about it. I prefer to have the if else and keep the logic together.

[calvincestari]

Also, if we move the check into the if statement below then the validation will be done twice because a field can be both a list type and and a composite type.

[calvincestari]

This test now becomes part of the compilation stage tests.

[calvincestari]

@AnthonyMDev this PR now has the entity and list disallow logic. I still need make the change to condense the ValidationOptions into a sub struct but the rest is ready for another pass.

[AnthonyMDev]

Thanks so much @calvincestari, I know this one was a lot harder than we expected!