Collect database schema information (specific to tables)

We need to be able to calculate some hash (?) or other unique identifier of table schema defined in HAF database. Above feature will be required in 2 cases:

• when hived starts using already filled database - then dedicated checks should be added to verify if existing schema is matching to hfm extension and hived itself (actually sql_serializer)
• when someone would like to perform a HAF database upgrade
• when database snapshot is loaded, altough here probably sql failure will eliminate risks of data damage