Re-organize Vue code #1: Vue directory

[kevreth]

Currently the Vue code is scattered among different directories under /src/ and the components directory is a flat list of components. Re-organize the Vue code to be more understandable.

1. Create a directory /src/vue/

2. Move the following directories to /src/vue/:

   1. components
   2. composables
   3. layouts
   4. pages
   5. router
   6. stores

3. Update import statements as needed.