Added ability to load Android build sources from file.

[reduz]

• If not present, the dialog asks to load build sources from a file.
• The export templates check now also verifies that build sources are installed and skips the template check.

This makes Android development easier.

Bugsquad edit: Fixes #36728.

[BastiaanOlij]

Will this extract the zip file and copy the templates into the android folder each time you export? Or will it only do so if the android folder isn't yet there?

I can foresee people forgetting to clear out the android folder after they build a new custom build and not realize they export with the version that was there before.

[reduz]

@BastiaanOlij this is more of an advanced use case when you use your own sources file. You can't unzip over existing directory.

[m4gr3d]

Looks good!

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.4.

[akien-mga]

@m4gr3d This has been cherry-picked already :)

[akien-mga]

So this doesn't seem to work so well UX wise, as the custom export templates manager is only shown when the official custom source template is not available. So it works well if you're using 4.0.dev or 3.5.beta with no official templates installed, but if you want to use a custom source template that you built for 3.4.stable, you can't access this dialog:

case FILE_INSTALL_ANDROID_SOURCE: {
	  if (p_confirmed) {
		  export_template_manager->install_android_template();
	  } else {
		  if (DirAccess::exists("res://android/build")) {
			  remove_android_build_template->popup_centered_minsize();
		  } else if (export_template_manager->can_install_android_template()) {
			  install_android_build_template->popup_centered_minsize();
		  } else {
			  custom_build_manage_templates->popup_centered_minsize();
		  }
	  }
} break;

IMO install_android_build_template should be removed, and custom_build_manage_templates should be used all the time, and provide options to install the official source template is available, or select a custom file.