Documentation maintenance (#595)

* Consistent quote style in `docs`

* Use emoji for Plus button

* Use hyperlinks in documentation

* Replace old MicroPowerManager URL

* Use Note admonitcons

* Split oneline per sentence

* Consistent use of `MicroPowerManager` of `MPM`

Author: dmohns

README.md

@@ -1,7 +1,7 @@
 <p align="center">
   <a href="https://github.com/EnAccess/micropowermanager">
     <img
-      src="https://micropowermanager.com/assets/images/Website_Illustrations_Logo.png"
+      src="https://micropowermanager.io/mpmlogo_raw.png"
       alt="OpenSmartMeter"
       width="320"
     >