init: Euro-Office Odoo 16.0 modules

Based on onlyoffice_odoo by Ascensio System SIA (ONLYOFFICE, LGPL-3).
Rebranded and adapted for Euro-Office by bring.out d.o.o.

Modules:
- eurooffice_odoo: base integration
- eurooffice_odoo_templates: document templates
- eurooffice_odoo_oca_dms: OCA DMS integration (replaces Enterprise documents)

All references renamed: onlyoffice -> eurooffice, ONLYOFFICE -> Euro-Office.
Original copyright notices preserved.

odoo-bringout-eurooffice-eurooffice_odoo/eurooffice_odoo/models/eurooffice_odoo.py

@@ -0,0 +1,21 @@
+import json
+
+from odoo import api, models
+
+from odoo.addons.eurooffice_odoo.utils import config_constants
+
+
+class EuroOfficeTemplate(models.Model):
+    _name = "eurooffice.odoo"
+    _description = "Euro-Office"
+
+    @api.model
+    def get_demo(self):
+        mode = self.env["ir.config_parameter"].sudo().get_param(config_constants.DOC_SERVER_DEMO)
+        date = self.env["ir.config_parameter"].sudo().get_param(config_constants.DOC_SERVER_DEMO_DATE)
+        return json.dumps({"mode": mode, "date": date})
+
+    @api.model
+    def get_same_tab(self):
+        same_tab = self.env["ir.config_parameter"].sudo().get_param(config_constants.SAME_TAB)
+        return json.dumps({"same_tab": same_tab})