[19.0][MIG] pos_sale_picking_keep

[alan196]

Migration of pos_sale_picking_keep from 18.0 to 19.0 (based on OCA/pos:19.0).

Migration changes

• Bump manifest version to 19.0.1.0.0.
• Add sale_stock dependency: pos_sale loads sale.order.picking_ids in the PoS data, a field provided by sale_stock. It is auto_install so it is normally present, but it is not pulled in the minimal CI install, which made the PoS fail to load with Invalid field 'picking_ids' on 'sale.order'. The module also operates on the sale order stock moves/pickings, so the dependency is required.
• Update the PoS test tour imports to the new 19.0 paths (tests/pos/tours/utils/* and tests/generic_helpers/dialog_util).
• Grant sales_team.group_sale_salesman in the test setup: in 19.0 point_of_sale.group_pos_manager no longer implies sales rights and the web onchange now checks create access, so creating the sale order raised AccessError.
• Use f-strings for the tour URLs (ruff UP031).
• Add readme/CONTRIBUTORS.md and regenerate the README.

Both PoS tours pass. Upstream PR: OCA#1576.

Note: also includes 4 Weblate (German) translation commits that are already in OCA/pos:19.0 and that this Jarsa branch did not yet have.

[jarsabot]

    **WARNING**: Could not link to Odoo task. Record ID not found in the title of the MR, supported formats:

{ record type }#{ number }

Available types: 'task#', 't#' (case insensitive)

Examples:

• task#123

• i#123

[jarsabot]

    **WARNING**: Could not link to Odoo task. Record ID not found in the title of the MR, supported formats:

{ record type }#{ number }

Available types: 'task#', 't#' (case insensitive)

Examples:

• task#123

• i#123

[jarsabot]

    **WARNING**: Could not link to Odoo task. Record ID not found in the title of the MR, supported formats:

{ record type }#{ number }

Available types: 'task#', 't#' (case insensitive)

Examples:

• task#123

• i#123

[jarsabot]

    **WARNING**: Could not link to Odoo task. Record ID not found in the title of the MR, supported formats:

{ record type }#{ number }

Available types: 'task#', 't#' (case insensitive)

Examples:

• task#123

• i#123