advotracker: reorganize the project using a crate based structure

* advotracker: the framework project
* crate/advotrackerdb: implementation of the database backend
* crate/advotrackerd: implementation of the backend (daemon)
* crate/adovtracker: implementaton of the application (CLI and GUI)

Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

crates/advotracker_client/examples/messages_test/data/mod.rs

@@ -0,0 +1,9 @@
+/*
+ * OrbTK - The Orbital Widget Toolkit
+ *
+ * Copyright 2021 Ralf Zerres <ralf.zerres@networkx.de>
+ * SPDX-License-Identifier: (0BSD or MIT)
+ */
+
+/// provides orbtk widgets constants
+pub mod constants;