Add other standard applications to the user guide

Running apt depends librem5-gnome gives a list of packages including librem5-gnome-phone and librem5-gnome-base. Expanding these and stripping out non-user-facing applications leaves us with these:

Name	Document	Notes
epiphany-browser	Yes	Web Browsing
evince	No
gedit	No
gnome-calculator	No
gnome-chess	No
gnome-clocks	Yes	Not yet decided
gnome-contacts	Yes	Managing Contacts
gnome-terminal	No
gnome-usage	No
gnome-weather	No
kgx	No
yelp	No
calls	Yes	Phone Calls
chatty	Yes	Sending and Receiving Messages
gnome-bluetooth	Yes	Part of Settings
gnome-control-center	Yes	Changing the Settings
gnome-getting-started-docs	No
gnome-initial-setup	Yes	Setting up Your Phone
gnome-online-accounts	Yes	Part of Settings
gnome-software	Yes	Installing New Applications
phosh	Yes	In A Quick Tour
squeekboard	Yes	Virtual Keyboard