Use encryption module from utils

Now that the encryption module has been moved from this app to utils, we
can remove it from here (along with its tests) and import it from utils
instead. This also renames the `encryption.py` file to `hashing.py`,
since it no longer contains the encryption class.

app/hashing.py

@@ -0,0 +1,10 @@
+from flask_bcrypt import generate_password_hash, check_password_hash
+
+
+def hashpw(password):
+    return generate_password_hash(password.encode('UTF-8'), 10).decode('utf-8')
+
+
+def check_hash(password, hashed_password):
+    # If salt is invalid throws a 500 should add try/catch here
+    return check_password_hash(hashed_password, password)