Frontend: Apollo MR pipelines - Extract mixins and eventhub logic from presentational components
To migrate the merge request pipelines table, we are going to need to remove the dependencies of children component from the mixins (which use REST, the pipeline stores and an eventhub) and instead make them emit native Vue events and let the parent components handle that as they may.
This will allow us, when building the new graphQL components, to simply build a new wrapper at the top that passes the data down and handle the mutations as needed.