Password reset docs and script

Replace the bash/perl gen_password script with a python one, and write a note
on how to use it.

scripts/gen_password

@@ -1 +0,0 @@
-perl -MCrypt::Random -MCrypt::Eksblowfish::Bcrypt -e 'print Crypt::Eksblowfish::Bcrypt::bcrypt("secret", "\$2\$12\$" . Crypt::Eksblowfish::Bcrypt::en_base64(Crypt::Random::makerandom_octet(Length=>16)))."\n"'

scripts/hash_password

@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+
+import argparse
+import bcrypt
+import getpass
+
+bcrypt_rounds=12
+
+def prompt_for_pass():
+    password = getpass.getpass("Password: ")
+
+    if not password:
+        raise Exception("Password cannot be blank.")
+
+    confirm_password = getpass.getpass("Confirm password: ")
+
+    if password != confirm_password:
+        raise Exception("Passwords do not match.")
+
+    return password
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Calculate the hash of a new password, so that passwords"
+                    " can be reset")
+    parser.add_argument(
+        "-p", "--password",
+        default=None,
+        help="New password for user. Will prompt if omitted.",
+    )
+
+    args = parser.parse_args()
+    password = args.password
+
+    if not password:
+        password = prompt_for_pass()
+
+    print bcrypt.hashpw(password, bcrypt.gensalt(bcrypt_rounds))
+