Updated the REST & Graphql clients to allow for TypeScript typings, a…

[FelixTellmann]

WHY are these changes introduced?

Fixes issue #193 - Adding Typescript types for REST & Graphql API Clients.

WHAT is this pull request doing?

• Added Types for all API Endpoints (extracted from the documentation site) and added namespaces for each endpoint with their individual requests.
• Updated the http_client, graphql_client and rest_client to accept the use of Generics.
• Updated the documentation to explain how types can easily be added to any request.
• Updated Typescript version for the package (required) to make typescript path matching work for mixed types (i.e. path: products/${number} for Product.GetById)
• Added a mergeQuery function that allows for merged Graphql queries, explained in the updated docs.

Type of change

• [ ] Patch: Bug (non-breaking change which fixes an issue)
• [x] Minor: New feature (non-breaking change which adds functionality)
• [ ] Major: Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• [ ] I have added a changelog entry, prefixed by the type of change noted above
• [x] I have added/updated tests for this change
• [x] I have documented new APIs/updated the documentation for modified APIs (for public APIs)

[FelixTellmann]

I've completed the CLA, please re-run the checks.

[paulomarg]

Hi @FelixTellmann, thank you for contributing! On the surface this seems quite interesting, we will look into it in more depth to see if we want to merge it!

[FelixTellmann]

Thank you for looking further into it. Let me know if I can be of any assistance in this. I've had a further look into the existing types that have been added to the package recently for each of the API versions. Currently, the types that I extracted from the Shopify.dev documentation site were based on the 2022/01 version.

[nickradford]

+1 to this PR

Having to manually cast the body after the client returns the response is clunky, this goes a way into improving the DX around using the provided client library.

[bkspace]

+1 we are also manually casting body everywhere

[zifahm]

+1 for PR. This PR would rapidly increase the DevX. Casting body is a no go.