Change primary keys SQL types to varchar

[xtreding]

Problem

At present Jitsu creates string columns with TEXT or character varying(65535) SQL type even if they are used in the primary key constraint. Downside: data type text requires more space in RAM and on disk and it is slower to process.

Solution

• [ ] Change all big strings types such as TEXT or character varying(65535) to VARCHAR(255).
• [ ] Move size of VARCHAR - 255 into a constant