"Set storage" is confusing

[kimadactyl]

I would expect this to get me to pick a filename. Instead it's a directory where ics files will go.

Possible solutions:

1. Change button to "set directory" (simple)
2. On first time setup, prompt for this and give a bit more context before giving the main options and start a sep config page (hard)

[kimadactyl]

On loading this again yeah I think this should prompt you to make a folder on startup as you can't make a folder in the fyne picker either which seems confusing for folks

[wheresalice]

We could display a dialog.InfoBox every time you start the app if a directory isn't set and have that explain something about setting the directory.

Not sure what the wording of that should be though.