This commit introduces the capability for users to apply custom prompts defined in the configuration to a block. Key changes include:
- A new configuration string to store the custom prompt.
- A menu item 'Custom prompt on block'.
- Implementation of a function to apply the custom prompt to a block, mirroring the existing 'summarize block' functionality.

feat: Add custom prompt defined in configuration to apply on block

…whole page

…ext all children of the block

…ma supports native windows now)

Previously, generated cards with llama3 model were broken, because
llama3 was too chatty and provided front and back sides when asked for a
question. Update the prompt to make generation correct.

Improve prompt for card generation