A big refactor

[Andrew15-5]

Changes:

• improved template output formatting (a lot of changes)
• optimized conditional blocks in cargo-generate.toml
• default_platform in Dioxus.toml now supports "fullstack"
• renamed "TUI" to "tui"
• renamed "Warp" to "warp" (that's how it is officially written)

I still don't know whether to use lowercase for these 4 choices:

prompt = "What backend framework are you using?"
choices = ["Axum", "warp", "Salvo"]
default = "Axum"

prompt = "How do you want to create CSS?"
choices = ["Tailwind", "Vanilla"]
default = "Vanilla"