Meta-ticket: make all modules importable without sage.all

[tobiasdiez]

Currently many modules cannot be imported without prior loading of sage.all (or for other reasons). This is however needed for modularization and for running them with pytest.

They can be found using the following script (run via ./sage)

import importlib.util
import pathlib
for file in pathlib.Path().glob("src/sage/**/*.py"):
    try: 
        spec = importlib.util.spec_from_file_location("module.name", file)
        module = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(module)
    except:
        print(file)

Tickets:

• Prevent circular import of matrix space #34283
• Import cycles in Sage #21636

CC: @mkoeppe @soehms

Component: refactoring

Issue created by migration from https://trac.sagemath.org/ticket/33580