feat: modal draft

[golota60]

Draft for modals;

There's a problem with those which i am yet to figure out the best solution for. The problem is: in order to display a modal, we need it to be the topmost level component, so that we can always center it and use a semi-transparent background for a backdrop. But here's the thing - there's no good way to do this.

The potential solution: expose a modal_wrapper/oxytail_wrapper(if we want to be more general) that will wrap our app in a vertical stack with a dummy "modal container" accessible globally. Next, when we want to render a modal, we simply get that global container, and put our modal data into it. This solution is not ideal for two reasons:

• Only one modal will be accessible
• We increase the boilerplate to use oxytail.
• It doesn't seem like the best approach, but the only one that would work