prevent users from running as debug

We give a friendly message now. If you need to run as debug,
use `cargo run -- --debug` or `./target/debug/notedeck --debug`

We also remove the callstack feature because it doesn't seem
like you need it for widget callstacks.

Fixes: aafddf5acb ("debug: add crate features which enable egui DebugOptions")
Signed-off-by: William Casarin <jb55@jb55.com>

Cargo.toml

@@ -64,8 +64,6 @@ security-framework = "2.11.0"
 [features]
 default = []
 profiling = ["puffin", "puffin_egui", "eframe/puffin"]
-debug-widget-callstack = ["egui/callstack"]
-debug-interactive-widgets = []
 
 [profile.small]
 inherits = 'release'