Add flatpaks.

[jmarrero]

Add flatpaks I use to the image or a script that auto installs them on first boot.

Name                        Application ID
Bitwarden                   com.bitwarden.desktop 
Brave Browser               com.brave.Browser
Flatseal                    com.github.tchx84.Flatseal
Google Chrome               com.google.Chrome
Slack                       com.slack.Slack
Spotify                     com.spotify.Client
Visual Studio Code          com.visualstudio.code
Element                     im.riot.Riot
Obsidian                    md.obsidian.Obsidian
Calculator                  org.gnome.Calculator
Shotwell                    org.gnome.Shotwell
Sound Recorder              org.gnome.SoundRecorder
Signal Desktop              org.signal.Signal
VLC                         org.videolan.VLC
Zoom                        us.zoom.Zoom