[Feature] Add metrics in MMEditing-1.x to MMEval

[LeoXing1996]

What's the feature?

MMEval has been released, and we are adding metrics in MMEditing-1.x to MMEval now, PRs from the community are welcome. You can refer to SSIM, PSNR, SNR, MAE and MSE.

To make the community fully aware of the progress, we list the progress here. Please feel free to leave a message and create a PR if you are willing to participate in any one of the files.

Metric list:

• [ ] Connectivity Error
• [ ] Gradient Error
• [ ] Matting MSE
• [ ] MS-SSIM
• [ ] NIQE
• [ ] SAD
• [ ] SWD

Any other context?

No response