Odoo Release Updates

[IMP] product, *: simplify product variant management

[FIX] account_fleet,hr_expense: vehicle sent in XML

[IMP] test_lint, *: Indexing of `Many2one` fields used in `related` fields

[IMP] hr_expense: remove dead record `Expense invoice`

[IMP] hr/hr_expense: enable link to existing bill to avoid duplicates

[IMP] hr_expense: back2basics expense & split view

[IMP] account: Allow reconciliation on all accounts

[FIX] hr_expense: prevent attachment leakage when posting multiple expenses

[FIX] hr_expense: require vendor for company-paid expenses using SEPA

[IMP] web,*: follow up for M3.1 style commit

[IMP] *: use widget "boolean_checkbox" to have checkbox on small screen

[FIX] product, hr_expense, point_of_sale: enable zoom on product images

[FIX] hr_expense: use the company of the expense for the payment journal entry

Refactors tracking API to use simpler methods, adds mail.track.mixin, and improves test coverage across modules.

[IMP] *: use type="bytes" in data files

[REF] web: add this. in rendering context

[REF] web: add this. in rendering context

[REF] *: migrate type="base64" to "bytes"

[IMP] account: improve performance of is_used computation

[FIX] hr_expense: avoid singleton error when opening expenses

[REF] hr, *: run rendering context migration script

[REF] *: Run script to replace t-ref by t-custom-ref

[IMP] hr_expense: remove tax amount from expense form view

[REF] *: remove url from js file tours

[IMP] hr_expense: add manual correction to expenses

[IMP] mail: update tracking API

[FIX] hr_expense: use employee company when creating from message

[FIX] hr_expense: skip encrypted files from expenses report PDF

[IMP] account,*: change payment states to paid,reconciled

[IMP] mail: cleanup track naming and usage