Implement an Gaussian Merger

[bhashemian]

One strategy to merge patches that we are already supporting in SligingWindowInferer is to use Gaussian weights to blend the patches together. To support this feature in the new design, a Gaussian Merger is required to be implemented.

Ref: #5837

[bhashemian]

@vikashg may I know what is the reason to close this issue?!

[vikashg]

@drbeh I think it was completed no as it was merged on Jun 22, 2023 ? If it is not we can reopen. We are trying to get a handle on all the open issues and see what are completed or inactive etc.

[bhashemian]

@vikashg this issue is only mentioned that merged PR, and it does not resolve it.