Add option to keep schema enum order for code generating

[viico]

Hi,

This is a PR related to issue #1760. We want to can keep schema enum order when generating code and not sort them alphabetically. This PR keep sort by default but add an option to don't.

I added a test and I update only for typescript generation. I don't know if it could be interesting for another generation.

TODO:

• [ ] Update CHANGELOG.md* with your change (include reference to issue & this PR)
• [ ] Make sure all of the significant new logic is covered by tests
• [ ] Rebase your changes on master so that they can be merged easily
• [ ] Make sure all tests and linter rules pass

*Make sure changelog entries note which project(s) has been affected. See older entries for examples on what this looks like.

[apollo-cla]

@viico: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Apollo Contributor License Agreement here: https://contribute.apollographql.com/

[viico]

I fixed unit tests but "ci/circleci: NodeJS 10" still failing, I don't see why.

[cdaz5]

this bug has been a thorn in our side for a while now ... anything i can do to help push this merge along? happy to help just LMK

[RebMeir]

We also faced the same problem.. anything we can do to push it?

[StasKeiss]

Can this be pushed to the main branch? This bug is really a big issue for us.

[Shirane85]

This is a major issue. We now need to create duplicates of the enums in order to support the existing code of the client. This is terrible.

[SamuelEls]

Is this completely forgotten feature?