`shiny create` drop `--template` parameter

[gadenbuie]

template should not require the --template flag

# 👍 😊
shiny create dashboard
shiny create chat-ai-ollama

# 👎 😥
shiny create --template dashboard
shiny create --template chat-ai-ollama

[gadenbuie]

We have

shiny create myapp

in our docs, which seems like it would create a the basic-app template in myapp?

But shiny create myapp doesn't work and I think most people would rather use the template id for shiny create (which then populates the directory) than to have the primary argument of shiny create be the name of the directory.

Those docs would become

shiny create basic-app
shiny export basic-app site