Draft: Add Support for Batching

[arikaufman]

This draft introduces modifications to support batching. The batching stack will be developed in parallel with the regular stack. Batched changes will be released incrementally, layer by layer, to allow easier review.

@tekaratzas, I’m thinking we could review these changes layer by layer. Once we’re confident in the full batching flow, we can swap out the main flow with the batched version.

Do we want to:

1. Create separate PRs for each layer and review/merge them one by one, or
2. Create one large PR in a separate subdirectory, then perform the swap in a follow-up PR?

[arikaufman]

Output Projection Batching
The changes required for output projection batching are now complete. These changes are in development under the batch_mode directory. As of now, I plan to continue updating this PR with support for each layer, as I progress.

[arikaufman]

Feed Forward Batching
The changes required for the feed forward layer of batching are now complete (tests included).