Rename Python test files because they no longer contain just imports
cxxll::python_analyzer: Fix nested attribute extraction

We did not visit the child nodes of attribute ASTs.
cxxll::python_analyzer: Minor refactoring in Python script
cxxll::python_analyzer: Extract function definitions
cxxll::python_analyzer: Extract class definitions
SQL schema: Add table symboldb.python_function_def
rpm_load: Make test for the presence of Python analysis results more robust
database::add_python_function_def(): New member function
rpm_load: Load table symboldb.python_function_def
SQL schema: Add table symboldb.python_function_def
database::add_python_class_def(): New member function
rpm_load: Load table symboldb.python_class_def