Epic Macro UX Patterns

During research for https://gitlab.com/gitlab-org/gitlab-ce/issues/43807, I've asked people if they use certain features or if they know of it being used within GitLab.

One of the larger issues that I came across with the features of GitLab that people seem to have a problem with is their larger connection to each other. For example, the Epics. It's hard to:

1. Connect issues to epics because you can't edit epics from issues and you can't edit issues from epics.
2. Enter issues into epics from the epic side or the issue side.
3. Moving quickly is just not possible right now.

This UX pattern can be applied across all products within GitLab.

cc @victorwu