reduced and adjusted db history scheme and added a few example queries to log db transactions
reduced and adjusted db history scheme and added a few example queries to log db transactions

GFZ-Centre-for-Early-Warning/REM_RRVS,GFZ-Centre-for-Early-Warning/REM_RRVS,GFZ-Centre-for-Early-Warning/REM_RRVS,GFZ-Centre-for-Early-Warning/REM_RRVS,GFZ-Centre-for-Early-Warning/REM_RRVS