docs: add docs for property mappings, switch to material theme

docs/policies.md

@@ -6,6 +6,8 @@ There are two different Kind of policies, a Standard Policy and a Password Polic
 
 ## Standard Policies
 
+---
+
 ### Group-Membership Policy
 
 This policy evaluates to True if the current user is a Member of the selected group.
@@ -44,6 +46,8 @@ This policy allows you to send an arbitrary HTTP Request to any URL. You can the
 
 ## Password Policies
 
+---
+
 ### Password Policy
 
 This Policy allows you to specify Password rules, like Length and required Characters.