cli(app/create): Ask for directory to create the app in

[xdoardo]

This PR introduces a mechanism that asks users the directory they want to save their app in in case the default app directory is not empty.

A bit more context:

Currently "wasmer app create" assumes that you just want to use the current directory.
This is not how most users will usually use this.

They won't do: mkdir bla; cd bla; wasmer app create.
Rather they will want to do wasmer app create , and have the result in bla.
The command should prompt for a target directory (with it optionally being .).
Should also have a flag to specify it in non-interactive mode.
The default should probably remain . to not break things, also in non-interactive mode.

[syrusakbary]

@xdoardo I assume this doesn’t affect the behavior of Wasmer deploy in a full dir, right?

[xdoardo]

If running wasmer deploy does not end up calling wasmer app create then no, it does not change. If wasmer deploy is called in a directory that does not contain a manifest (nor an app.yaml) then it falls back to wasmer app create which will eventually ask the user a directory to store their app in.

Note, however, that creating apps from existing directories was previously explicitly unsupported. In the near future we'll want to adopt a create mechanism (and thus a deploy mechanism as well) that allows to create an app from an existing project with no manifest, if I understood correctly.

[syrusakbary]

then it falls back to wasmer app create which will eventually ask the user a directory to store their app in.

So, it will affect? Basically for wasmer deploy in a directory with files and without a app.yaml it should prompt to deploy the own directory. While wasmer app create can prompt to create in a new directory. Both behaviors should work well @xdoardo

[syrusakbary]

I got confused here. Chatted with @xdoardo and we are in alignment with this solution. Approving