[enhancement]: Prompt Blocks

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Contact Details

_No response_

### What should this feature add?

Instead of prompt templates, it would be nice to be able to apply multiple templates as blocks within the actual prompt.

Having check boxes in the template drop-box to enable/disable prompts. Enabled prompts then appear in the actual prompt field as a drag able block for positioning (maybe with editable colours).

I'd also like to be able to add default prompts to LoRAs, also adding a block to the actual prompt field.

I feel this would enable a user to create their own 'main' and 'sub' templates, along with 'scene', 'subject' and 'style' templates.

### Alternatives

_No response_

### Additional Content

Template folders should also be considered.