ui: add initial Profile hover previews

The idea with these is that on notedeck you can just hover your cursor
over a profile link to see the profile. I just have a stub for now, but
full design coming soon after.

Also simplify the preview system even further with a macro. In the
future I imagine we can grep every preview in the codebase, and then
include this as a string inside this macro. This is some kind of
template metaprogramming insanity but in theory it could work.

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

src/profile.rs

@@ -1,7 +1,7 @@
 use nostrdb::ProfileRecord;
 
 pub fn get_profile_name<'a>(record: &'a ProfileRecord) -> Option<&'a str> {
-    let profile = record.record.profile()?;
+    let profile = record.record().profile()?;
     let display_name = profile.display_name();
     let name = profile.name();