dchat: add to darkfi workspace and fix bug in dchat Cargo.toml

Cargo.toml

@@ -49,7 +49,7 @@ members = [
     "src/contract/consensus",
     "src/contract/deployooor",
 
-    #"example/dchat",
+    "example/dchat",
 ]
 
 [dependencies]

example/dchat/Cargo.toml

@@ -21,7 +21,6 @@ simplelog = "0.12.1"
 url = "2.5.0"
 
 serde_json = "1.0.108"
-serde = {version = "1.0.193", features = ["derive"]}
 toml = "0.8.8"
 libsqlite3-sys = {version = "0.27.0", features = ["bundled-sqlcipher-vendored-openssl"]}