[Prompt Matrix] Support for negative prompt + delimiter selector

[hoblin]

Prompt Matrix is a great script but it lacks two important features:

• the ability to test negative prompt
• the ability to change the delimiter between variable strings for those who don't want commas in prompt

Additional notes and description of your changes

Added two Radio blocks for prompt type selection and delimiter. Formated options with gr.Row and gr.Column

Environment this was tested in

• OS: Windows
• Browser: tested on Chrome, Mac Safari, and iOS Safari
• Graphics card: n/a for the changes

Screenshots or videos of your changes Desktop large: Desktop medium: Mobile: