Enable optimistic locking

Purpose/Overview:
Enable optimistic locking for most tables. Seeing a 409 error would be an improvement over modifications that fail quietly and affect data integrity. It will also help us to see how frequent these issues are in production.

Requirements/Scope:
Enable optimistic locking with failure for the following tables:
budget
transaction
budget_expense_class
fund
group_fund_fiscal_year
expense_class
fiscal_year
fund_type
groups
ledger
ledger_fiscal_year_rollover

Approach:

• Add the _version attribute to the matching schemas in acq-models. It might be needed to look beyond the obvious, for instance shared_budget should also have the attribute. Merge that PR first.

"_version": {
   "type": "integer",
   "description": "Record version for optimistic locking"
 },

• Change the table definitions in schema.json to add "withOptimisticLocking": "failOnConflict".
• Return a 409 HTTP code when a conflict occurs, which can be detected by the SQL error code 23F09. For that, modify ResponseUtils$handleFailure and check ((PgException)cause).getCode().
• Update API and module versions with a major change.

Acceptance criteria:

• All unit tests and integration tests (finance, orders, cross-modules) pass.
• The MODFISTO-260 test parallel-update-order-lines-different-orders reports a 409 instead of quietly updating the budgets wrongly.