Implement Gtk Network Status (#165)

Implemented
- Switch reacts to burrow socket and network changes 
- meson as build system
- Basic diagnostics to ensure burrow is installed properly
- Flatpak / Meson Building

burrow-gtk/src/config.rs.in

@@ -0,0 +1,8 @@
+#[allow(unused)]
+pub const ID: &str = @ID@;
+#[allow(unused)]
+pub const VERSION: &str = @VERSION@;
+#[allow(unused)]
+pub const LOCALEDIR: &str = @LOCALEDIR@;
+#[allow(unused)]
+pub const GETTEXT_PACKAGE: &str = @GETTEXT_PACKAGE@;