Feat: Add grid view feature to the issue page

What does this MR do and why?

Related issue: #323095 #387022(MVC1)

Related JH issue: https://jihulab.com/gitlab-cn/gitlab/-/issues/2150

This MR implements MVC1 described in this #387022. It revamps the issue page by adding a grid view (while keeping the list view) for both group and project issues. Users can customize the order of fields in the grid view and add or remove fields (with "id" and "title" being fixed fields), and their customization config is cached in the browser.

The buttons for subscribing, importing, exporting, and other actions that used to be located above the tabs are now moved into the menu. Additionally, this MR introduces a button for switching between the list view and grid view, as well as a button for configuring the grid view.

This feature is controlled by the feature flag issues_grid_view.

/cc @mtan-gitlab @JeremyWuuuuu

Screenshots or screen recordings

before

after

How to set up and validate locally

1. Open the feature flag issues_grid_view in rails console. (::Feature.enable(:issues_grid_view))
2. Go to the issue page of any group or project.
3. Observe.

MR acceptance checklist

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