Enhancement: [Theme existing plugins]

### Describe the feature you'd like
[First mentioned here](https://github.com/dracula/tmux/issues/36#issuecomment-642210300)
There are innumerable possible features that someone could want as part of their tmux theme. We can accommodate this much more effectively by relying on the many existing plugins for the tmux ecosystem rather than writing new modules to add each of these features. #42 will probably need to be completed first in order to achieve this.