Remove old ui and storybook crates (#3125)

This PR deletes the old `ui` and `storybook` crates in favor of their
newer variants that we'll be landing to `main` in the near future.

### Motivation

These crates are based off the old version of GPUI 2 (the `gpui2`
crate).

At this point we have since transitioned to the new version of GPUI 2
(the `gpui3` crate, currently still on the `gpui2` branch).

Having both copies around is confusing, so the old ones are going the
way of the dinosaurs.

Release Notes:

- N/A

crates/ui/src/components/context_menu.rs

@@ -1,65 +0,0 @@
-use crate::prelude::*;
-use crate::theme::theme;
-use crate::{
-    v_stack, Label, List, ListEntry, ListItem, ListItemVariant, ListSeparator, ListSubHeader,
-};
-
-#[derive(Clone)]
-pub enum ContextMenuItem {
-    Header(&'static str),
-    Entry(Label),
-    Separator,
-}
-
-impl ContextMenuItem {
-    fn to_list_item(self) -> ListItem {
-        match self {
-            ContextMenuItem::Header(label) => ListSubHeader::new(label).into(),
-            ContextMenuItem::Entry(label) => {
-                ListEntry::new(label).variant(ListItemVariant::Inset).into()
-            }
-            ContextMenuItem::Separator => ListSeparator::new().into(),
-        }
-    }
-    pub fn header(label: &'static str) -> Self {
-        Self::Header(label)
-    }
-    pub fn separator() -> Self {
-        Self::Separator
-    }
-    pub fn entry(label: Label) -> Self {
-        Self::Entry(label)
-    }
-}
-
-#[derive(Element)]
-pub struct ContextMenu {
-    items: Vec<ContextMenuItem>,
-}
-
-impl ContextMenu {
-    pub fn new(items: impl IntoIterator<Item = ContextMenuItem>) -> Self {
-        Self {
-            items: items.into_iter().collect(),
-        }
-    }
-    fn render<V: 'static>(&mut self, view: &mut V, cx: &mut ViewContext<V>) -> impl IntoElement<V> {
-        let theme = theme(cx);
-        v_stack()
-            .flex()
-            .fill(theme.lowest.base.default.background)
-            .border()
-            .border_color(theme.lowest.base.default.border)
-            .child(
-                List::new(
-                    self.items
-                        .clone()
-                        .into_iter()
-                        .map(ContextMenuItem::to_list_item)
-                        .collect(),
-                )
-                .set_toggle(ToggleState::Toggled),
-            )
-        //div().p_1().children(self.items.clone())
-    }
-}