LocalBackendModifyOperation.java: Extracted methods createPasswordPolicyState(), preProcessPasswordModification().

Renamed:
- handleSchemaProcessing() to processNonPasswordModifications()
- processInitialSchema() to processModification()
- processInitialAddSchema() to processAddModification()
- processInitialDeleteSchema() to processDeleteModification()
- processInitialReplaceSchema() to processReplaceModification()
- processInitialIncrementSchema() to processIncrementModification()

- handleInitialPasswordPolicyProcessing() to processPasswordPolicyModifications()
- processInitialAddOrReplacePW() to preProcessPasswordAddOrReplace()
- processInitialDeletePW() to preProcessPasswordDelete()

- handleAccountStatusNotifications() to generatePwpAccountStatusNotifications()