Add new --no-gui parameter

[CommandMC]

Launching Heroic without the UI is now possible with this parameter. Together with launching a game (heroic://launch/AppName), this now allows for a fully headless game launch, similar to HBL (HBL's still faster, since we have to load all of Heroic first)

Closes #1361

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Use the following Checklist if you have changed something on the Backend or Frontend:

• Tested the feature and it's working on a current and clean install.
• Tested the main App features and they are still working on a current and clean install. (Login, Install, Play, Uninstall, Move games, etc.)
• Created / Updated Tests (If necessary)
• Created / Updated documentation (If necessary)

[flavioislima]

Need to test but looks good codewise.
Also, --no-gui sounds better maybe?
Because I know that other software use the --gui, protontricks for instance.
although doesn't really matter once we document it or add a cli --help

[CommandMC]

I agree, I'll change it to --no-gui. Just took it directly from the issue

[flavioislima]

Tested and works pretty good. I liked it that it closes Heroic after the game closes. This will probably be useful then adding heroic on other tools :)

[lublak]

Whether it's --no-ui or --no-gui or --please-dont-show-a-graphical-user-interface. I'm fine with anything.
Whereas "gui" in linguistic usage is mostly used for the interface. Rather more rarely just "ui".

[rkr87]

Did this make it into 2.3.3?

[lublak]

@rkr87 the 2.3.3 build is 4 days ago but the feature is merged yesterday. Soooo it think not.

[rkr87]

The Flatpak release of 2.3.3 only became available today on Flathub. 🙂