Simplify build-system further

Remove Fragile from the list of dependencies

It is not necessary for building 'gio' anymore,
since the upgrade to 'glib v2_58'.

Remove "online" and "reset_lock" Meson-options

Building Squeekboard should work offline.

Use a single "Cargo.toml"-file instead of splitting it into parts

and putting it back together when building.

Part-of: <https://gitlab.gnome.org/World/Phosh/squeekboard/-/merge_requests/623>

Cargo.toml

@@ -0,0 +1,66 @@
+[package]
+name = "rs"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+name = "rs"
+path = "@path@/src/lib.rs"
+crate-type = ["staticlib", "rlib"]
+
+# Cargo can't do autodiscovery if Cargo.toml is not in the root.
+[[bin]]
+name = "test_layout"
+path = "@path@/src/bin/test_layout.rs"
+
+[[example]]
+name = "test_layout"
+path = "@path@/examples/test_layout.rs"
+
+[[example]]
+name = "find_orphan_layouts"
+path = "@path@/examples/find_orphan_layouts.rs"
+
+[features]
+zbus_v1_5 = []
+clap_v4 = []
+
+[dependencies]
+maplit = "1.0.*"
+serde = { version = "1.0.*", features = ["derive"] }
+serde_yaml = "0.8.*"
+bitflags = "1.3.*"
+clap = { version = "4.4.*", features=["std"], default-features = false }
+zbus = "1.9.*"
+zvariant = "2.10.*"
+zvariant_derive = "2.10.*"
+xkbcommon = { version = "0.5.*", features = ["wayland"] }
+
+[dependencies.cairo-rs]
+version = "0.18.*"
+
+[dependencies.cairo-sys-rs]
+version = "0.18.*"
+
+[dependencies.gdk]
+version = "0.18.*"
+
+[dependencies.gio]
+version = "0.18.*"
+features = ["v2_58"]
+
+[dependencies.glib]
+version = "0.18.*"
+features = ["v2_58"]
+
+[dependencies.glib-sys]
+version = "0.18.*"
+features = ["v2_58"]
+
+[dependencies.gtk]
+version = "0.18.*"
+features = ["v3_24"]
+
+[dependencies.gtk-sys]
+version = "0.18.*"
+features = ["v3_24"]