Remove PropertyManager for Preferences

Remove the PropertyManager and PropertyKey from the Preferences implementation. This simplifies the implementation a bit. The PropertyManager was not used and was left as a configurable value of the PreferencesProvider. As a result of this change, the configurable flag has been removed.

The database schema has also be changed to reflect the removal of PropertyManager:

• The PREFS_NODE_PROPERTY_KEY table has been removed.
• The PREFS_PROPERTY_KEY table has been removed.
• The PREFS_PROPERTY_VALUE table has been changed. The following columns have been removed:

• PROPERTY_KEY_ID INTEGER,
• BOOLEAN_VALUE INTEGER,
• DATETIME_VALUE TIMESTAMP,
• LONG_VALUE INTEGER,
• DOUBLE_VALUE DOUBLE,
• TEXT_VALUE VARCHAR(254)
  The following columns have been added:
• PROPERTY_NAME VARCHAR(100),
• PROPERTY_VALUE VARCHAR(254)

The foreign key FOREIGN KEY (NODE_ID) REFERENCES PREFS_NODE (NODE_ID) on PREFS_PROPERTY_VALUE has not been added. It still causes foreign key violations with OJB 1.0.3 for cascade deletes.