Assembly: Implement Bill Of Materials (#14198)

* Assembly: Implementation of BOM

* Assembly: BOM: make it possible for BOM to be made without an assembly.

src/Mod/Spreadsheet/App/Sheet.cpp

@@ -516,6 +516,11 @@ App::Range Sheet::getRange(const char* name, bool silent) const
     return cells.getRange(name, silent);
 }
 
+std::tuple<App::CellAddress, App::CellAddress> Sheet::getUsedRange() const
+{
+    return cells.getUsedRange();
+}
+
 /**
  * @brief Get a map with column indices and widths.
  * @return Map with results.