Add time-zone into database tables' timestamp/date fileds

[taojing2002]

Currently, Metacat stores the timestamp and date data without the timezone information. It interprets they are with the default timezone of JVM (system). So this can cause an issue if the operator change the default timezone of the host.

In the systemmetadata table, it has:

date_uploaded           | timestamp without time zone |
date_modified           | timestamp without time zone |

In the access_log table, it has:

date_logged | timestamp without time zone |

In the both xml_documents and xml_revisions table, it has

date_created | date |
date_updated | date |

The date type doesn't have timezone information either. The value looks like:

 date_created | date_updated 
--------------+--------------
 2024-04-30   | 2024-04-30
 2024-04-30   | 2024-04-30