[Doc] Add new sets of blueprint for embedding model with no pre and post processing functions

[mingshl]

Is your feature request related to a problem?
we have a set of blueprint for embedding model here https://opensearch.org/docs/latest/ml-commons-plugin/remote-models/blueprints/ and also available in github,
Earlier, we have the these blueprint for embedding model which has pre and post processing function to standardize the model input and output format, so that it can be use for neural search query.
But now that we have ml inference processor that allow users to map the model input and output format, then user can register connector and model without pre and post processing function, We want to provide a new set of blueprint for embedding model with no pre and post processing function.

What solution would you like?
write new sets of blueprint with no processing functions for embedding models in ml-commons repo.

update documentation website for the following outline:

Model Blueprints for Vector Search

OpenSearch provides two approaches for implementing embedding models, depending on your needs:

Standard Blueprints (Using ML Inference Processor)

Recommended for new implementations

These blueprints use the ML inference processor to handle input/output mapping, offering:

• Simpler implementation
• Direct model registration
• Flexible input/output mapping through the processor
• [List of available models with links]

Legacy Blueprints (With Pre/Post Processing)

For existing implementations or specific customization needs

These blueprints include pre- and post-processing functions, suitable when you need:

• Custom preprocessing logic
• Specific output formatting requirements
• Compatibility with existing implementations
• [List of available models with links]

Choosing the Right Blueprint

1. For new implementations: Use the standard blueprints with the ML inference processor
2. For existing systems: Continue using legacy blueprints or consider migrating
3. For custom processing: Choose legacy blueprints if you need specific preprocessing logic

[jngz-es]

@mingshl , is it a feature needed code changes or just documentation?