Kernel: Rewrite whole device structure

We now have DevFileSystem which is derived from RamFileSystem. All
devices are RamInodes. We don't have separate DeviceManager anymore.
To iterate over devices, you can loop througn every inode in devfs.

kernel/include/kernel/FS/Pipe.h

@@ -30,8 +30,6 @@ namespace Kernel
 		virtual dev_t dev() const override { return 0; } // FIXME
 		virtual dev_t rdev() const override { return 0; } // FIXME
 
-		virtual BAN::StringView name() const override { return ""sv; }
-
 		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) override;
 		virtual BAN::ErrorOr<size_t> write(size_t, const void*, size_t) override;