Changing data type of sync_source_info column to accommodate more characters

Insert values for the column "sync_source_info" under table "x_ugsync_audit_info" can go beyond the maximum length of column. (currently limit is VARCHAR 4000).

Now changing data type to different db flavours as follows :

mysql              : VARCHAR => MEDIUMTEXT

oracle             : VARCHAR => CLOB

postgres        : VARCHAR => TEXT

sqlanywhere : VARCHAR => TEXT

sqlserver        : VARCHAR => nvarchar(max)