Add import and export data, and custom config data type mappings

1. add
   (1) import and export data;
   (2) custom config data type mappings and edit data type info before converting;
   (3) statistic: table column content max length;
   (4) diagnosis: primary key column is nullable;
   (5) quick search.
2. enhance
   (1) sql query editor intellisense;
   (2) data editor.
   3.accumulated bugs fix.