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/profile/picture.rs

@@ -16,10 +16,14 @@ impl<'cache, 'url> egui::Widget for ProfilePic<'cache, 'url> {
 
 impl<'cache, 'url> ProfilePic<'cache, 'url> {
     pub fn new(cache: &'cache mut ImageCache, url: &'url str) -> Self {
-        let size = 32.0;
+        let size = Self::default_size();
         ProfilePic { cache, url, size }
     }
 
+    pub fn default_size() -> f32 {
+        32.0
+    }
+
     pub fn no_pfp_url() -> &'static str {
         "https://damus.io/img/no-profile.svg"
     }