feat: add seamlyme welcome screen

[DSCaskey]

This adds a Welcome screen dialog in place of the existing Splash screen. Offers more options and control than a QSplashScreen does.

• Allows for form layout with more than a single message. The existing splash screen was just a background pixmap, which lacks the ability to translate.
• Has an OK button that is user dependent and does not rely on a timed delay.
• Allows for the user to choose whether to see the dialog again.
• Adds some default startup user prefs such as the Decimal separator that has been an issue for some new users when not set correctly. CheckBox text changes from "Use OS options" to "User locale"
• Specifically addresses the 3D Look body scan conversion. Also removes the code to attempt creating a conversion email.

Resolves issue #1053

[ghost]

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[csett86]

Overall looks very good, I just did small fixups (reverting to the old immediate processing of the commandline args to avoid two seamly windows under macos) and removing the splash screen leftovers

[csett86]

mac build is failing due to a missing updated agreement in the Apple developer account:

Error: HTTP status code: 403. A required agreement is missing or has expired. This request requires an in-effect agreement that has not been signed or has expired. Ensure your team has signed the necessary legal agreements and that they are not expired.

@slspencer could you please help us out here at https://developer.apple.com/account

[DSCaskey]

@csett86

reverting to the old immediate processing of the commandline args to avoid two seamly windows under macos

Since the delay = zero, we can just remove the QTimer call processCommandLine() directly.

Also moved the "NOTing" of showWelcome in the assignment. Makes it a bit clearer. If showWelcome was used more than once, would have to NOT every occurance.

[DSCaskey]

@csett86

For some reason removing the QTimer call in main() is causing the SeamlyMe command line tests to fail?? Makes no sense, but just putting back the way it was.

[csett86]

I also did not follow through on the timer, just reverted it to the old value (same as you)