feat: support aten.log1p converter

[chohk88]

Description

A converter for the torch.ops.aten.log1p operation (elementwise log(1 + x))

Fixes # (issue)

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• [x] My code follows the style guidelines of this project (You can use the linters)
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas and hacks
• [ ] I have made corresponding changes to the documentation
• [x] I have added tests to verify my fix or my feature
• [x] New and existing unit tests pass locally with my changes
• [x] I have added the relevant labels to my PR in so that relevant reviewers are notified