Created new merge checks component

What does this MR do and why?

Created a new merge checks component which will be used for when the merge when checks pass feature is enabled.

This component will fetch the merge checks from the GraphQL API and then render the returned list. It will either render the returned message through the message.vue component or it can be overriden.

To override you add a new property to the COMPONENTS object in the merge_checks.vue component with the key name matching the identifier returned from the GraphQL API.

Screenshots or screen recordings

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

• Run bin/rake frontend:fixtures
• Install storybook yarn storybook:install
• Build storybook yarn storybook:start
• Visit http://localhost:9002/?path=/story/vue-merge-request-widget-merge-checks--default

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

#423111 (closed)