Book generation: the process is too slow

[spirosChv]

The book generation workflow runs on CPU via github actions. The complete process needs approx. 3.5 hours. This is too much especially during the course. The process must be faster.

Possible workarounds:

1. Run on GPUs (either locally, or on cloud service gpus)
2. Use the cache options, so that the book will run only for the updated notebooks, if possible. See here

[spirosChv]

1. Run on GPUs (either locally, or on cloud service gpus)

Added a local machine to execute all notebooks --> Several CUDA errors. Needs debugging

[spirosChv]

The book generation leads also to several error:

1. Unhandled exception. System.IO.IOException: No space left on device : '/home/runner/runners/2.304.0/_diag/Worker_20230606-082117-utc.log'
2. System.IO.IOException: No space left on device : '/home/runner/runners/2.304.0/_diag/Worker_20230525-115206-utc.log'

The tweak for now is to run the book generation on a local machine with GPU.

Potential fix: run automatically the process on a local machine.

[iamzoltan]

Yea, I think trying to solve the cache is the best bet, although it ends up only being stored for about a week.