Remove 'type' column from 'wallet' table - upgrade knex (tech debt)

[orhoj]

Task description
The type column of the wallet table is unused, and in some cases it contains an incorrect value. The column should be dropped. Dropping the column is non-trivial as SQLite does not support this in an alter table command. We may have to upgrade the knex dependency to be able to turn off foreign_key constraint checks during the migration, as it does not seem to be possible to do that while keeping the onCreate method that turns on the check with our current version.