Organize which routes are prefixed with "/api"

[isaacdonaldson]

This PR aims to organize which routes are prefixed with /api and which are not. I moved where /api is prepended into the individual controllers and out of the routes section in the app.rs file, making all starters have the same basis. Changing the scaffold generation to prepend /api only when the -k api option is chosen, and not adding it for -k htmx and -k html (for the views) is easier to reason about.

Before this change, scaffold generation would add a route as /<resource_name> to the saas starter, but as /api/<resource_name> to rest-api and lightweight-service. Instead, the new change would have -k api add new routes as /api/<resource_name> while -k htmx and -k html add them just as /<resource_name>. In this case, whether /api is added is based on whether you are using the -k api option, and not based on the starter template you chose.

[jondot]

@isaacdonaldson i think this will unlock the bigger picture here: #834

[isaacdonaldson]

@jondot - Is there anything holding this up?

[jondot]

@isaacdonaldson not at all, we've just made some changes to allow this to be part of a bigger picture of simplifying the starters

I will split this PR into the templates part and starter part will manually migrate the changes to a different existing PR