init package and add first subpackages

src/paveit/helper/filehasher.py

@@ -0,0 +1,22 @@
+import hashlib
+from io import BytesIO
+
+
+def calc_hash_of_bytes(buf: BytesIO):
+    """ calculate the hash of the file """
+
+    algo = hashlib.sha1()
+
+    buffer_size = 65536
+    buffer_size = buffer_size * 1024 * 1024
+
+    while True:
+        data = buf.read(buffer_size)
+        if not data:
+            break
+        algo.update(data)
+
+    hex = algo.hexdigest()
+
+    return hex
+