chore(bee api -driver=postgres): change Postgres API generate PrimaryKey and Auto tag

[maplerichie]

… Key with Serial (Auto increme$

Change in Methods:

1. func (postgresDB) GetColumns()
2. func isSQLDecimal()
3. func extractIntSignness()
4. func extractDecimal()

Description

1. Update query, extra will return "auto_increment" instead of blank "", Primary Key can work toget$
2. Increase type of decimal
3. Fix return INT length
4. Fix return DECIMAL types precision