Create a way for the user to change their home directory

From thao:

> as we installed the new version of the plugin, it didn't ask me for a home directory anymore, the last dev release was also didn't ask for one -- but I haven't checked if it's use the same home directory yet, and I can't check it now as the "Select an existing model" is not available for me

We should create a way for the user to

- check where their current home directory is located
- give an option to change this folder to another folder on their system