Option to play music without interrupting castle music

[jez9999]

Preliminary checks

• [X] I've checked that there aren't other open issues on the same topic.

Describe the problem requiring a solution

In the original game you could select "CD stereo without opera". When you did this, you got the background music, and it kept playing without changing when you went into a castle screen. I like this and I'm used to it. Please provide such an option in fheroes2.

Describe the possible solution

Add a music option similar to "CD stereo without opera" so that background music is not interrupted by castle music when a castle screen is opened.

Additional info

No response