add AvalonStudio.Shell code.
ADD
.gitmodules
+[submodule "WalletWasabi.Dependencies/AvalonStudio.Shell"]
+ path = WalletWasabi.Dependencies/AvalonStudio.Shell
+ url = https://github.com/VitalElement/AvalonStudio.Shell.git

ADD
WalletWasabi.Dependencies/AvalonStudio.Shell
+Subproject commit 53e58fffe00f76f8eeaae59d01938b3bfbfb75d0

add AvalonStudio.Shell code.