Enable libadwaita feature of Relm4, remove unused direct Tokio dep

Cargo.lock

@@ -924,18 +924,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72a2903cd7736441aac9df9d7688bd0ce48edccaadf181c3b90be801e81d3d86"
 dependencies = [
  "pin-project-lite",
- "tokio-macros",
-]
-
-[[package]]
-name = "tokio-macros"
-version = "2.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af407857209536a95c8e56f8231ef2c2e2aff839b22e07a1ffcbc617e9db9fa5"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
 ]
 
 [[package]]
@@ -1122,5 +1110,4 @@ dependencies = [
  "gtk4",
  "libadwaita",
  "relm4",
- "tokio",
 ]