Adding Mock Model + Test Directory

[mvanniasingheTT]

This PR adds in the mock model + mock offline inference script + a new test directory.
The mock model can be used for quick iteration and development without a TT device to test benchmarking/stress-testing/eval procedures in either an online or offline setting.

[milank94]

It's confusing at the moment having two sets of code changes where one is a copy of #21. Hard to see which code pieces you would like the focus of the review on.

My recommendation is either:

• Change the target branch to tstesco/evals-benchmarking-structure
• if targeting main, don't include those code changes that are in evals and benchmarking structure #21

[tstescoTT]

It's confusing at the moment having two sets of code changes where one is a copy of #21. Hard to see which code pieces you would like the focus of the review on.

My recommendation is either:

* Change the target branch to `tstesco/evals-benchmarking-structure`

* if targeting `main`, don't include those code changes that are in [evals and benchmarking structure #21](https://github.com/tenstorrent/tt-inference-server/pull/21)

This makes sense, I'll add that to enable making changes that require other unmerged changes on another branch we shouldnt merge onto the other branch as the default but wait until that branch is merged to main then change the new leaf branch to point to main as well. The process would be:

1. PR for review should start against the other branch for reference (tstesco/evals-benchmarking-structure in this case).
2. Don't merge PR into the base branch unless desired by the base branch author (to avoid confusion with other PR review).
3. Once the other branch is merged to main the PR can be switched to target main.

[milank94]

@mvanniasingheTT I think the code could benefit by running a formatter and linter. Consider the Ruff VSCode extension as an easy plugin to run.

CC: @tstescoTT

[milank94]

Looks great. Pending the merge of #21.

[milank94]

@mvanniasingheTT I think that you forgot to change the target branch?