No progress displayed during dictionnary cache building

[tigre-bleu]

This is not a big issue, just some nice improvement.

When a very big dictionary is used (like rockyou2021), a long time can be spent building cache (around 15 min in my case). During this period, Crackerjack only displays "Please Wait..." with no progress bar. This could be confusing as to why it does not start cracking.

Technically it could be added as under the hood, hashcat reports the progress in building cache.