entgql(WhereInput): remove graphql-go/graphql

[giautm]

We replace graphql-go/graphql with vektah/gqlparser

This commit includes small break changes, that is will not
update the existed input in the schema.
You HAVE TO remove the duplicated input from your schema.

Refactor WhereInput feature for ent/ent#2351

[giautm]

BC: always overwritten ent.gql

In the previous version, the EntGQL extension will check if the input data type exists in the ent.gql file, it will be left as is.
With this version, all operations are always-overridden. Therefore, if you declare the input data type in the ent.gql file, it will be deleted and replaced with the version of EntGQL.

[crossworth]

@giautm do you think it would be possible to add support for some kind of "hook" on the whereFilters part?

Maybe allowing us (users) to provide a custom genWhereInputs and export the default one (and use it when not provided), maybe export the others methods related to it as well (so we can use they on our genWhereInputs user-side implementation).

Right now, even if we change the templates for the where filters, there is no way to change the ent.graphql file, I need to add custom filters/directives on the generated file.

[giautm]

Hey @crossworth, thank you for your kind words.

I plan to add some hooks for modifying the schema after we generate it from the graph. But, currently, the WhereInput and GQL Schema aren't connected yet to become a single schema. I will continue on it after this PR get merged.

[a8m]

I love it, just a few comments before accepting.

Great work @giautm.

[a8m]

Great work 💯

[a8m]

Thanks for landing this @giautm. For next time, please use <package>: <message> as a commit format.

Also, your PRs were merged to gqlparser, so you're welcome to add the printer change here 😃