[Feat]: enable pylint on samples dir and optionally on test files

### Describe the feature

Currently only enabled on src/ in tox, but missing from Megalinter.

Also investigate if all tests really need `# pylint: skip-file` and improve where possible.

### Use Case

Code style improvements.

### Proposed Solution

- [ ] Enable pylint in megalinter
- [ ] Fix findings in samples
- [ ] Investigate why test files are configured for `# pylint: skip-file`

### Acknowledgements

- [ ] I may be able to implement this feature request