README.md: explain what this is about a bit more

Also some white-space changes to the source more readable.

README.md

@@ -1,16 +1,20 @@
 # Koji osbuild
 
-This project provides osbuild integration with Koji. This is done via three
-plugins:
+This project provides osbuild integration with Koji. It makes it possible
+to build images and other OS artifacts via osbuild-composer through koji,
+This is done via three plugins:
 
  - Koji **hub** plugin: Provides a new XMLRPC API endpoint that clients
    can use to create new `osbuildImage` Koji tasks.
+
  - Koji **builder** plugin: Handles `osbuildImage` Koji tasks and will talk
    to osbuild-composer to create new composes via composer's Koji API.
+
  - Koji **cli** plugin: Adds a new `osbuild-command` to the existing `koji`
    command line client. This will then use the new XMLRPC API to request a
    new compose.
 
+
 ## Configuration
 
 The builder plugin needs to be configured via a `builder.conf` file that