Remove unused username functionality (#2699)

Author: cp-at-mit

users/utils.py

@@ -12,43 +12,6 @@
 User = get_user_model()
 log = logging.getLogger(__name__)
 
-USERNAME_SEPARATOR = "-"
-# Characters that should be replaced by the specified separator character
-USERNAME_SEPARATOR_REPLACE_CHARS = "\\s_"
-# Characters that should be removed entirely from the full name to create the username
-USERNAME_INVALID_CHAR_PATTERN = (
-    rf"[^\w{USERNAME_SEPARATOR_REPLACE_CHARS}{USERNAME_SEPARATOR}]|[\d]"
-)
-
-USERNAME_TURKISH_I_CHARS = r"[ıİ]"
-USERNAME_TURKISH_I_CHARS_REPLACEMENT = "i"
-
-# Pattern for chars to replace with a single separator. The separator character itself
-# is also included in this pattern so repeated separators are squashed down.
-USERNAME_SEPARATOR_REPLACE_PATTERN = (
-    rf"[{USERNAME_SEPARATOR_REPLACE_CHARS}{USERNAME_SEPARATOR}]+"
-)
-
-
-def _reformat_for_username(string):
-    """
-    Removes/substitutes characters in a string to make it suitable as a username value
-
-    Args:
-        string (str): A string
-    Returns:
-        str: A version of the string with username-appropriate characters
-    """
-    cleaned_string = re.sub(USERNAME_INVALID_CHAR_PATTERN, "", string)
-    cleaned_string = re.sub(
-        USERNAME_TURKISH_I_CHARS, USERNAME_TURKISH_I_CHARS_REPLACEMENT, cleaned_string
-    )
-    return (
-        re.sub(USERNAME_SEPARATOR_REPLACE_PATTERN, USERNAME_SEPARATOR, cleaned_string)
-        .lower()
-        .strip(USERNAME_SEPARATOR)
-    )
-
 
 def is_duplicate_username_error(exc):
     """