[19.0][MIG] connector: Migration to 19.0

[mkoeck]

Main changes

• New security model support

  • Add a res.groups.privilege record introduced in 19.0 and adapted the existing res.groups record accordingly

• Test suite updates for 19.0 API

  • Replace deprecated self.env2.reset() calls with self.env2.transaction.reset() in tests.
  • Adapt tests to the now read-only env.context:
    • Remove direct writes to self.env.context.
    • Use self.env() to create a new environment instead
  • Remove / replace references to demo data:
    • Demo loading order changed in 19.0, so some demo external_ids are no longer guaranteed to exist.
    • Tests now rely on explicit test data instead of demo records.

Functional impact

• No functional feature changes are intended.
• The goal of this PR is to make the module compatible with Odoo 19.0 while preserving existing behavior where possible.

Dependencies

This PR has been tested against the following non-merged branches of dependent modules:

• component: https://github.com/Sanazzzmi/connector/tree/19.0-mig-component
• component_event: https://github.com/Sanazzzmi/connector/tree/19.0-mig-component_event
• queue_job_base: https://github.com/tishmen/queue/tree/pr/queue_job_base