Maintenance release, new guides and updated docs

Fix

• Fix AverageMeter for n > 1 cases.

Breaking Changes

• Delete batch object after iteration complete.
• Don't store data loader in the state of engine.

New Features

• Return metrics from fit method the same way as from from validate.
• Use constructor from BuildModel to be able to user pass build_order.

Docs

New guides on:

• Custom metrics.
• Partial weights loading and manipulation.
• Model export.
• Custom callbacks.
• LR schedulers.

Other improvements:

• New solutions of competitions to examples.
• Improve docstrings in many places.

Chore

• Use pyproject.toml.
• Update GitHub Actions versions.
• Update dependencies.
• Use ruff linter.

Full Changelog: v1.0.0...v1.1.0