Adding contacts assumes $HOME/hush-ng/ exists

[leto]

events.js:163 Uncaught Error: ENOENT: no such file or directory, open '/Users/jonathanleto/hush-ng/contacts.json'

which causes all kinds of bad problemas afterward. @rjanetzek i think we should move this data inside of .hush/, just like the hushlist reference implementation that uses .hush/list. How about .hush/ng/ for this data?

[leto]

For now we can keep it in the same place, but we must check that it exists and show a UI error if something goes wrong, like a permission error

[TheTrunk]

In the initial setup it creates hush-ng folder and downloads hushd, hush-cli into hush-ng/bin so it assumes correctly that hush-ng folder exists when it created it.
If so, move everything to .hush then but imo the installation and uninstallation has to be considered firstly