Remove the `graphql` support from the core

[pkarw]

What is the motivation for adding / enhancing this feature?

The current graphql support is pretty buggy and un-flexible. We've reworked the whole graphql support on the backend with https://github.com/DivanteLtd/storefront-api. But the current searchAdapter is not compatible with this. I tried fo fix it in the https://github.com/DivanteLtd/vue-storefront/tree/feature/storefront-api-graphql-support but only to get even more frustrated :-)

GraphQL support will be added in the vsf-next for Magento2 I guess and for now the searchAdapter for graphql: https://github.com/DivanteLtd/vue-storefront/tree/develop/core/lib/search/adapter/graphql should be moved to an optional module within the src/search (this path is officially supported) or pm package

[pkarw]

@kkdg we need to update the docs regarding this change. With graphql support in the src/search as optional module it will be still available - however unsupported/deprecated

[kkdg]

@pkarw all right! It was the heavily updated part in the meantime. I will edit them accordingly, thanks.