FE: Use GraphQL for Jira issues list

This issue encapsulates frontend work for refactoring the Jira Issues list to use GraphQL. At a high level, this will involve:

Adding an instance of Apollo to the Vue app: ee/app/assets/javascripts/integrations/jira/issues_list/jira_issues_list_bundle.js
Creating a client-side query + resolver for the Jira Issues REST endpoint
- Ideally, we will use a similar schema to regular GitLab issues. frontend should collaborate with backend (#329075 (comment 573518868))
Refactor ee/app/assets/javascripts/integrations/jira/issues_list/components/jira_issues_list_root.vue to use the @client query for fetching the Issues list

Counterpart backend issue: #329075

Edited May 20, 2021 by Tom Quirk