Add missing docstrings

Add missing docstrings to modules, classes and functions. Refactor
existing docstrings that are not correctly formatted.

Issue: HIC-170
Change-Id: I766830259b897f8c2d931f3b53ce935e82b161fd
diff --git a/crashreports/admin.py b/crashreports/admin.py
index 97b32e0..c45eabd 100644
--- a/crashreports/admin.py
+++ b/crashreports/admin.py
@@ -1,3 +1,5 @@
+"""Admin interface for manipulating devices, crashreports and heartbeats."""
+
 from django.contrib import admin
 from crashreports.models import Crashreport
 from crashreports.models import Device
@@ -7,19 +9,27 @@
 
 @admin.register(Crashreport)
 class CrashreportAdmin(admin.ModelAdmin):
+    """Manage Crashreports as admin user."""
+
     pass
 
 
 @admin.register(HeartBeat)
 class CrashreportAdmin(admin.ModelAdmin):
+    """Manage HeartBeats as admin user."""
+
     pass
 
 
 @admin.register(LogFile)
 class CrashreportAdmin(admin.ModelAdmin):
+    """Manage LogFiles as admin user."""
+
     pass
 
 
 @admin.register(Device)
 class CrashreportAdmin(admin.ModelAdmin):
+    """Manage Devices as admin user."""
+
     pass