Rebuild comments tab on submissions and projects with htmx and alpinejs

[frjo]

Goals are:

• [ ] Load comments on demand to improve performance of submission and project detail view.
• [ ] Solid implementation of inline editing of comment, current implementation is fragile and a hack.
• [ ] Merged view of comments and activities so the activity feed tab can be removed.

Related #3048

What should we name the new tab to? In vill include both comments and activities.

There is space so maybe just a straight forward "Comments and Activities" or something to that effect?