WIP: Move issue_card_inner ee diffs

ee MR https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/11003

What does this MR do?

This MR moves ee-specific code from assets/javascripts/boards/components/issue_card_inner.vue

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content