Minimax H3 Multi Ref workflow for low VRAM

Use Minimax H3 Director instead of previous Ksampler subgraph

add a button in Model subgraph to enable TE-Speed (OSS)

add a button in Model subgraph to Low VRAM option

add lora stack

add new user guide

Keep interface clean and tidy, un-spaghettify

用Minimax H3 Director取代前版本的Ksampler subgraph

在Model subgraph加了一個開關給TE-Speed (OSS)

在Model subgraph加了一個選擇給Low VRAM