Updated model and checkpoints to run in tf v2.

[brunomcebola]

Changes:

1. Folder Structure:

   • Moved the existing codebase to a new folder named tf_v1.
   • Created a new folder named tf_v2 to accommodate the updated version.

2. Migration:

   • Migrated the model and associated checkpoints from TensorFlow v1 to TensorFlow v2 within the tf_v2 folder.

3. Environment Setup:

   • Added requirements.txt and .python-version files to both the tf_v1 and tf_v2 folders to ensure proper environment setup and compatibility with respective TensorFlow versions.

[brunomcebola]

@diegolascasas