feat: add initial sub task list modal

[AliNisarAhmed]

• [x] Have you followed the contributing guidelines?
• [x] Are you working/merging into develop?
• [ ] Do all tests pass?

If appropriate:

• [ ] Have you added new tests for additional functionality?

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[AliNisarAhmed]

@smallhadroncollider Still working on this, but starting this PR for your comments/suggestions. I am calling the new modal "TaskList" (and named all the modules for it similarly), but "SubTaskList" could also be used. Chose "S" for showing the modal for now.

[smallhadroncollider]

All looking good so far