feat/option to load extraction models once instead of everytime partition pdf function called

[hasansalimkanmaz]

Is your feature request related to a problem? Please describe.
I am using partition_pdf function. Everytime, I call the function, it loads the relevant models into memory. This results in significant delays in processing.

Describe the solution you'd like
I would like to have a paramter in partition_pdf function to allow loading the model once into the memory throughout the life cycle of the application. This way, there will not be any need to load the model again.

[hasansalimkanmaz]

If you can guide me on how to do it, I may allocate some time on my side to implement this feature depending on how complex it is.