Implement caching and optimization for Redner template handling

• Added ormcache to improve performance by caching template retrieval in _get_cached_template.
• Refactored template processing logic:
  • Introduced _to_odoo_template to centralize transformation of external templates into Odoo-compatible format.
  • Simplified template computation in _compute_template and _compute_template_data using cached templates.
• Removed redundant methods (to_cache) and consolidated logic for clarity.

models/redner_template.py

@@ -449,6 +449,6 @@
         # We do NOT depend on the API for consistency here
         # So raised error should not result block template deletion
         for record in self:
-            if record.redner_id:
+            if record.redner_id and record.allow_modification_from_odoo:
                 try:
                     self.redner.templates.account_template_delete(record.redner_id)
@@ -453,7 +453,12 @@
                 try:
                     self.redner.templates.account_template_delete(record.redner_id)
-                except Exception:
-                    pass
+                except Exception as e:
+                    # Log the exception if needed (for debugging purposes)
+                    logger.warning(
+                        "Failed to delete redner template for record %s: %s",
+                        record.id,
+                        {str(e)},
+                    )
 
         return super().unlink()