Fix “Failed to remove the module $MODULE” warnings

[antepusic]

Description

Upon the removal of query modules (e.g. when shutting down Memgraph), warnings such as these are consistently logged:

[2023-04-05 16:35:36.374] [Warning] Failed to remove the module mgp_networkx from sys.modules
[2023-04-05 16:35:36.378] [Warning] Failed to remove the module mgp_igraph from sys.modules
[2023-04-05 16:35:36.428] [Warning] Failed to remove the module igraphalg from sys.modules

This PR fixes the issue by relocating two helper modules (mgp_networkx and mgp_igraph) from /python to /python/mage.

Pull request type

• [x] Bugfix

Related issues

#212

######################################

Reviewer checklist (the reviewer checks this part)

Module/Algorithm

• [ ] Core algorithm/module implementation
• [ ] Query module implementation
• [ ] Unit tests
• [ ] End-to-end tests
• [ ] Code documentation
• [ ] README short description
• [ ] Documentation on memgraph/docs

######################################

[antoniofilipovic]

@antepusic can we close this?

[antepusic]

@antoniofilipovic I think we’re fine closing this – it was a harmless issue even when the PR was opened

[antepusic]

Closing stale PR per my above message