Link issues and their resolutions together without merging

### Problem Statement

Often times the same bug causes multiple Sentry issues. For example, let's say a request to an API endpoint that calls a a DB func and function2 asynchronously times out. This leads to 3 issues: one from the root request and 2 from the called functions.

However, we don't want to merge the issues because we don't want future events that *are* independent of one another to get conflated.

It's tedious to have to go into each issue and hyperlink the main issue and its resolution. It would also help us declutter Sentry so that we can focus on the most actionable items.

### Solution Brainstorm

In addition to merging issues, it'd be great if we could *link* issues to say that when Issue1 is resolved, Issue2 through Issue5 are also resolved.

This feature should also work with Linear and Git integrations so that if Issue1 has a Linear ticket/branch associated with it and it's merged, then Issue1 and its linked issues are all resolved.

This link between issues should appear in the Activity tab of each issue so that if a user clicks into Issue2, they can see the comments from Issue1.

In the issue overview page, if a user selects multiple issues & links them, they should have the option to add a comment 1 (which will be linked to all the others).

### Product Area

Issues