Defold: Add a setting under [build] within the config file to disable donation buttons for Steam build

[subsoap]

Is your feature request related to a problem? Please describe (REQUIRED):
Steam rejects "Donate" buttons in builds, they want you to pay through Steam. There are two places where these need to be disabled in the Steam release build.

Describe the solution you'd like (REQUIRED):
In the config file add a field under [build] to say if it's a Steam build or not. If it's a Steam build then disable the donate / support text / swap them to other messages like "We are grateful to our supporters!" / change text to "Source Available on Github" and link to the repo.

[bootstrap]
resourcespath = 
launcherpath = 

[build]
version = 1.2.177
editor_sha1 = 15990df1280c63c1744849d6456237c6411f593e
engine_sha1 = f7778a8f59ef2a8dda5d445f471368e8bd1cb1ac
time = 2020-12-18T20:28:49.967999
channel = editor-alpha
steam = true
...

When making Steam builds, use existing builds and inject the steam = true line under the channel to enable Steam build.

[subsoap]

The steam = false can also be set by default to false in

/editor/scripts/bundle.py

Then it's that much easier to swap it to true for Steam releases.

[subsoap]

If you want to automate releasing to Steam it can be done. I think a script like in /build_tools would need to be made release_to_steam.py to automate it unless it already exists elsewhere.

Instead of remaking it entirely could have the release_to_steam.py just grab the last github release to modify then upload to Steam.

[subsoap]

The value to check in Clojure for the screens would be

System.getProperty("defold.steam");

I don't know if those are always strings or not would need to check further.

String isSteam = System.getProperty("defold.steam");
isSteam = (isSteam == null || isSteam.isEmpty()) ? "false" : isSteam;

This could be swapped to "GitHub Source" and link to the https://github.com/defold/defold/ in Steam builds
/editor/src/clj/editor/app_view.clj

(handler/defhandler :donate :global
  (run [] (ui/open-url "https://www.defold.com/donate")))
...
               {:label "Donate"
                :command :donate}

/editor/src/clj/editor/app_view.clj

(UIUtil/stringToTextFlowNodes (:sponsor-push controls) "Support the continued development of Defold\n[Become a community sponsor](https://www.defold.com/community-donations)!")

This could be swapped to the same. "Source Available on GitHub"

[subsoap]

Some of the tips may also need to be screened too

https://github.com/defold/defold/blob/editor-dev/editor/resources/tips.txt

Checking for donate / donation within a tip and picking another one on Defold version may work.

[subsoap]

Changing the wording may help too. Blender got approved, this is its wording.

[subsoap]

https://github.com/defold/defold/pull/5468