Move md5sum implementation to fs_utils

Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>

test_utils/filesystem/file.py

@@ -21,11 +21,7 @@ class File(FsItem):
         return fs_utils.diff(str(self), str(other_file))
 
     def md5sum(self, binary=True):
-        output = TestRun.executor.run(
-            f"md5sum {'-b' if binary else ''} {self.full_path}")
-        if output.exit_code != 0:
-            raise Exception(f"Md5sum command execution failed! {output.stdout}\n{output.stderr}")
-        return output.stdout.split()[0]
+        return fs_utils.md5sum(str(self), binary)
 
     def read(self):
         return fs_utils.read_file(str(self))