Move gradually to std::filesystem

[teusbenschop]

It is now time to use the newer filesystem calls from the std::filesystem library.

To keep testing whether it keeps working after the move.

• Cloud.
• Linux tarball.
• Cloud Ubuntu package.
• Client Ubuntu package.
• Debian packages - assumed to be good - not yet tested.
• Android - 5 out of 6 devices had crashes in C++ - remain with the C API - to be retried later.
• iOS - It builds with std::filesystem but the app is very slow in the simulator - to be retried later.
• macOS
• Windows - may requirer newer Visual Studio
• If Windows done: Remove thestd::wstring: Nope, this is still needed for other calls.
• If done: Remove DIRECTORY_SEPARATOR
• If done: Remove USE_STD_FILESYSTEM

[teusbenschop]

When enabling std::filesystem on Android, several devices had native crashes. This are crashes in C++.

Device(s) with issues
Google Pixel 6 (oriole) - Android 12
Google Pixel 5 64-bit only (redfin_64) - Android 13
Google Pixel 7 (panther) - Android 13
Motorola Motorola G20 (java) - Android 11
Generic Small Desktop (x86) (SmallDesktop.x86) - Android 12L

Exceptions
Native crash of org.bibledit.android
Native crash of org.bibledit.android
Native crash of org.bibledit.android
Native crash of org.bibledit.android
Native crash of org.bibledit.android
Native crash of org.bibledit.android