ui: add profile picture hover animation

I wanted to practice doing animation in egui, so here is a simple
profile picture hover affect. When you mouse over a profile picture, it
get slightly bigger.

Signed-off-by: William Casarin <jb55@jb55.com>

src/ui/anim.rs

@@ -0,0 +1,19 @@
+pub fn hover_expand(
+    ui: &mut egui::Ui,
+    id: egui::Id,
+    size: f32,
+    expand_size: f32,
+    anim_speed: f32,
+) -> (egui::Rect, f32) {
+    // Allocate space for the profile picture with a fixed size
+    let default_size = size + expand_size;
+    let (rect, response) =
+        ui.allocate_exact_size(egui::vec2(default_size, default_size), egui::Sense::hover());
+
+    let val = ui
+        .ctx()
+        .animate_bool_with_time(id, response.hovered(), anim_speed);
+
+    let size = size + val * expand_size;
+    (rect, size)
+}