Remove vendored usvfs and Windows-only usvfs code paths

The Linux port uses its own in-process FUSE VFS (FuseConnector), so
usvfs was dead weight: libs/usvfs/ was never built, usvfsconnector.cpp
was explicitly REMOVE_ITEM'd from the source list, and every call site
was already guarded by #ifdef _WIN32 with a working Linux branch (the
Windows build is also broken on this branch, since FUSE3 is a hard
find_package dependency).

- Drop libs/usvfs/ and src/src/usvfsconnector.{cpp,h}
- Collapse #ifdef _WIN32 / usvfs include branches in organizercore,
  mainwindow, settings, util, spawn
- Remove getUsvfsVersionString() and the "usvfs: ..." log field
- Remove vfs32/64DLLName APPPARAMs (nothing reads them)
- Relabel About dialog "usvfs:" row to "VFS: FUSE 3"

1 files changed, 0 insertions, 34 deletions

diff --git a/libs/usvfs/.gitignore b/libs/usvfs/.gitignore
deleted file mode 100644
index 1c1dec2..0000000
--- a/libs/usvfs/.gitignore
+++ /dev/null
@@ -1,34 +0,0 @@
-# build outputs:
-/bin
-/lib
-/test/bin
-/build*
-/install
-
-# local overides
-/vsbuild/external_dependencies_local.props
-
-# build intermediates:
-/vsbuild/Release
-/vsbuild/ReleaseTest
-/vsbuild/Debug
-/vsbuild/DebugTest
-/vsbuild32
-/vsbuild64
-CMakeUserPresets.json
-
-# test "side effects"
-/test/temp
-
-# VS generated files:
-.vs
-*.aps
-*.vcxproj.user
-msbuild.log
-
-/stderr.log
-/stderr_32.log
-/stdout.log
-/stdout_32.log
-
-.vscode