Disable debug info in the dev profile by default

This does not affect the release profile and it significantly speeds
up compilation.  In the rare cases where panics are not sufficient to
debug something you can manually enable this again.

Cargo.toml

@@ -5,6 +5,9 @@ authors = ["Delta Chat Developers (ML) <delta@codespeak.net>"]
 edition = "2018"
 license = "MPL-2.0"
 
+[profile.dev]
+debug = 0
+
 [profile.release]
 lto = true