feat: merge cartsnitch/api into api/ subdirectory

Consolidate API gateway service into monorepo.
Squashed from https://github.com/cartsnitch/api main (89bacb1).

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/cartsnitch_api/auth/passwords.py

@@ -0,0 +1,11 @@
+"""Password hashing and verification with bcrypt."""
+
+import bcrypt
+
+
+def hash_password(password: str) -> str:
+    return bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    return bcrypt.checkpw(plain_password.encode(), hashed_password.encode())