[MU4] New XML and MXL File Icons

[liamrosenfeld]

This brings the new XML and MXL designs from #3269 but without the excessive amount of over-engineering for the build system (we got quite carried away).

This could also be an opportunity to provide those file icons on macOS and Windows—I would be more than happy to add it, I would just need to first be pointed in the right direction.

• I signed CLA
• I made sure the code in the PR follows the coding rules
• I made sure the code compiles on my machine
• I made sure there are no unnecessary changes in the code
• I made sure the title of the PR reflects the core meaning of the issue you are solving
• I made sure the commit message(s) contain a description and answer the question "Why do those changes fix that particular issue?" or "Why are those changes really necessary as improvements?"

[liamrosenfeld]

I think I figured out how to add that document icon on macOS (last commit), though I'm still not sure about Windows.

[Jojo-Schmitz]

For Windows maybe check #5421 (comment), but that probably won't help for the icons here, as MuseScore doesn't register itself for MusicXML files?

[liamrosenfeld]

@Jojo-Schmitz, should I create a new instance of:

<RegistryValue Root="$(var.RegistryRoot)" Key="SOFTWARE\Classes\MuseScore.mscx" Value="MuseScore File" Type="string" />
            <ProgId Id="MuseScore.mscx" Description="MuseScore File" Advertise="no" Icon="$(var.ExeId)" IconIndex="1">
                <Extension Id="mscx" Advertise="no">
                    <Verb Id="open" TargetFile="$(var.ExeId)" Command="Open" Argument="&quot;%1&quot;" />
                    <MIME Advertise="no" ContentType="application/x-musescore+xml" Default="no" />
                </Extension>
            </ProgId>

to register itself for MusicXML files?

[Jojo-Schmitz]

I don't think so. Maybe better asking @anatoly-os

[Jojo-Schmitz]

rebase needed (but hold it until the master build got fixed)

[liamrosenfeld]

@Jojo-Schmitz, I rebased. 👍

@anatoly-os, do you have any guidance on how I could expand this new icon to the Windows target?

[anatoly-os]

It's up to @Tantacrul to decide whether we want to have better MXL icons. Martin, what do you think?