Introduce auth cache settings

- TTL for cache values
- Maximum capacity for caches

enterprise/security/src/main/java/org/neo4j/server/security/enterprise/auth/EnterpriseAuthManagerFactory.java

@@ -78,7 +78,10 @@ public AuthManager newInstance( Config config, LogProvider logProvider )
             // TODO: Load pluggable realms
         }
 
-        return new MultiRealmAuthManager( internalRealm, realms, new AuthCache.Manager( Clocks.systemClock(), 100, 100 ) );
+        long ttl = config.get( SecuritySettings.auth_caching_ttl );
+        long maxCapacity = config.get( SecuritySettings.auth_cache_max_capacity );
+
+        return new MultiRealmAuthManager( internalRealm, realms, new AuthCache.Manager( Clocks.systemClock(), ttl, maxCapacity ) );
     }
 
     private static InternalFlatFileRealm createInternalRealm( Config config, LogProvider logProvider )

enterprise/security/src/main/java/org/neo4j/server/security/enterprise/auth/SecuritySettings.java

@@ -26,7 +26,9 @@
 import org.neo4j.helpers.HostnamePort;
 
 import static org.neo4j.kernel.configuration.Settings.BOOLEAN;
+import static org.neo4j.kernel.configuration.Settings.DURATION;
 import static org.neo4j.kernel.configuration.Settings.HOSTNAME_PORT;
+import static org.neo4j.kernel.configuration.Settings.LONG;
 import static org.neo4j.kernel.configuration.Settings.NO_DEFAULT;
 import static org.neo4j.kernel.configuration.Settings.STRING;
 import static org.neo4j.kernel.configuration.Settings.STRING_LIST;
@@ -140,4 +142,12 @@ public class SecuritySettings
                   "E.g. group1=role1;group2=role2;group3=role3,role4,role5" )
     public static Setting<String> ldap_authorization_group_to_role_mapping =
             setting( "dbms.security.realms.ldap.authorization.group_to_role_mapping", STRING, NO_DEFAULT );
+
+    @Description( "The time to live (TTL) for cached authentication and authorization info." )
+    public static Setting<Long> auth_caching_ttl =
+            setting( "dbms.security.realms.auth_caching_ttl", DURATION, "10m" );
+
+    @Description( "The maximum capacity for authentication and authorization caches (respectively)." )
+    public static Setting<Long> auth_cache_max_capacity =
+            setting( "dbms.security.realms.auth_cache_max_capacity", LONG, "10000" );
 }