Split into multiple crates

Cargo.toml

@@ -1,50 +1,2 @@
-[package]
-name = "musicus"
-version = "0.1.0"
-edition = "2018"
-
-[dependencies]
-anyhow = "1.0.33"
-async-trait = "0.1.42"
-diesel = { version = "1.4.5", features = ["sqlite"] }
-diesel_migrations = "1.4.0"
-discid = "0.4.4"
-fragile = "1.0.0"
-futures = "0.3.6"
-futures-channel = "0.3.5"
-gettext-rs = "0.5.0"
-gtk-macros = "0.2.0"
-gstreamer = "0.16.4"
-gstreamer-player = "0.16.3"
-isahc = "0.9.12"
-once_cell = "1.5.2"
-rand = "0.7.3"
-secret-service = "2.0.1"
-serde = { version = "1.0.117", features = ["derive"] }
-serde_json = "1.0.59"
-thiserror = "1.0.23"
-uuid = { version = "0.8", features = ["v4"] }
-
-[dependencies.gdk]
-git = "https://github.com/gtk-rs/gtk4-rs/"
-package = "gdk4"
-
-[dependencies.gio]
-git = "https://github.com/gtk-rs/gtk-rs/"
-features = ["v2_64"]
-
-[dependencies.glib]
-git = "https://github.com/gtk-rs/gtk-rs/"
-features = ["v2_64"]
-
-[dependencies.gtk]
-git = "https://github.com/gtk-rs/gtk4-rs"
-package = "gtk4"
-
-[dependencies.libadwaita]
-git = "https://gitlab.gnome.org/bilelmoussaoui/libadwaita-rs"
-package = "libadwaita"
-
-[dependencies.pango]
-git = "https://github.com/gtk-rs/gtk-rs/"
-features = ["v1_44"]
+[workspace]
+members = ["crates/*"]