Doc: make the project description more detailed

README.md

 # DIOT Monitoring Module (MoniMod)
 
-This is a SAMD21-based monitoring module for the DI/OT power supply
-and fan tray.
+The DIOT Monitoring Module (MoniMod) is a SAMD21-based PMBus
+monitoring module for
+the [DI/OT project's](https://www.ohwr.org/project/diot/wikis/home)
+power supply and fan tray. It can monitor the voltage and current for
+up to three power rails. It can also host up to three temperature
+sensors, and control up to three fans without requiring them to
+support PWM.
 
-*Disclaimer: this README is still incomplete, it will be properly
-populated in time.*
+Detailed documentation can be found at the
+project's [readthedocs page](https://diot-monimod.readthedocs.io).
 
 ## Repository structure
 

doc/source/overview.rst

 Overview
 ========
 
-The DIOT Monitoring Module (MoniMod) is a SAMD21-based monitoring
-module for the DI/OT project's [#DIOT]_ power supply and fan tray.
+The DIOT Monitoring Module (MoniMod) is a SAMD21-based PMBus
+monitoring module for the DI/OT project's [#DIOT]_ power supply and
+fan tray. It can monitor the voltage and current for up to three power
+rails. It can also host up to three temperature sensors, and control
+up to three fans without requiring them to support PWM.
 
 
 Repository Structure