feat: support bi-encoder models in TransformerSimilarityRanker

[Amnah199]

Is your feature request related to a problem? Please describe.
The current implementation of TransformerSimilarityRanker only supports cross-encoder models, which limits the use of bi-encoder models like ColBERT v2.0.

Related discussion: Colbert as reranker

Describe the solution you'd like
Update the TransformerSimilarityRanker or creating a new component to support bi-encoder models like ColBERT.

Describe alternatives you've considered
Leave the current implementation as is.

Additional context
Similar implementation: Llama ColbertRerank

[peteriz]

fastRAG is an extension of Haystack and has a Bi-encoder similarity ranker. You're invited to check it out here.
And also ColBERT and PLAID support ..

@julian-risch We will be happy to contribute the bi-encoder ranker upstream to Haystack.