[✨ feature] Issue detail page (body section)

[Fredkiss3]

Is your feature request related to a problem? Please describe.

This issue address only the rendering of the body of the issue with the header on the right, it is basically the same as #69 but will show the previewed body by default, the user can still edit, but they should only be able if the issue is theirs.

Describe the solution you'd like

• See body
• See issue revisions (public by everybody)
• Edit issue (same infos as adding issues)
• Can cancel the edition (should revert to body)
• Cannot edit issues where the user is not the author
• Show subscription button (not yet interactive, will work later)
• Show participants
• Show lock/unlock conversation button : if locked only the author can comment
• Can delete issue
• Can add reaction to issue (unless connected) => can only add one type of reaction per user and highlight reactions already made by the current user

Describe alternatives you've considered

N/A

Additional context

• We may want to use Suspense if markdown rendering is slow.
• In github normally, you can't edit labels, projects, or assignees (unless yourself) but in this project i will let people do as they want in their issues

Screenshot for ref :

• [NEXT-1143] Dev mode slow compilation vercel/next.js#48748 (comment)

• Are you willing to make a PR for this ?