Update integration sample - Shopify

[Simply007]

Brief bug description

After the rebranding from Kentico Cloud to Kentico Kontent there are still some samples that use old naming in branches named samples/*.

Until the end of October endpoint on domain kenticocloud.com stop working and there will be redirect performed:

• https://docs.kontent.ai/reference/api-changelog#a-api-urls-changed

Expected behavior

Transfer changes made in https://github.com/Kentico/kontent-sample-app-react/pull/140 to the samples/shopify branch

• Update dependency from kentico-cloud-delivery to @kentico/kontent-delivery
  • adjust the breaking changes
• Update dependency @chevtek/react-spinners to @simply007org/react-spinners
  • no breaking changes
• Rename Kentico Cloud to Kentico Kontent
• adjust travis.yml to use the correct domain for deployment

[obulaworld]

Hi @Simply007 , I can work on this.

[Simply007]

It is yours @obulaworld!