[Feature Request] Extend mustache module plugin support for knn

[night-owl-1709]

Is your feature request related to a problem? Please describe

We want to build mustache support for knn_vector fields for that we need to extend mustache module plugin so it can be used in knn repo.

Issue on knn repo: opensearch-project/k-NN#459

Describe the solution you'd like

Extending support for mustache module, like we have for painless.
Once the support is extended, it can be directly integrated into the KNN plugin

Related component

No response

Describe alternatives you've considered

No response

Additional context

No response

[night-owl-1709]

Will take up this issue