refactor: project structure (#9)

Split up project into multiple crates and use a Cargo workspace.

docs/README.md

@@ -0,0 +1,37 @@
+# AOOSTAR WTR MAX Screen Control
+
+- [asterctl usage](asterctl.md)
+- [Linux shell control commands](shell_commands.md) without using asterctl
+
+## Sensor Panels
+
+- [Sensor panels](sensor_panels.md)
+- [Custom sensor panels](sensor_custom_panel.md)
+
+### Sensor Modes
+
+Different sensor modes are supported:
+
+- [Sensor mode 1: Text](sensor_mode1_text.md)
+- [Sensor mode 2: Circular Progress](sensor_mode2_fan.md)
+- [Sensor mode 3: Progress](sensor_mode3_progress.md)
+- [Sensor mode 4: Pointer](sensor_mode4_pointer.md)
+
+### Sensor Data Sources
+
+The sensor value reading is separated from the `asterctl` tool.
+
+Sensor values are provided in separate text files and are automatically read when the file changes.  
+Only the file data source is supported at the moment, other sources like pipes, sockets etc. might be supported later.
+
+- [Text file data source](sensor_data_txt_file.md)
+
+### Sensor Data Providers
+
+- Proof of concept [Linux shell scripts](sensor_data_shell.md)
+- [sysinfo tool](sensor_data_sysinfo.md)
+
+## Development
+
+- [LCD Protocol](lcd_protocol.md)
+