Add is_colab() and is_kaggle() (#41)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

ultralytics/yolo/utils/files.py

@@ -1,6 +1,5 @@
 import contextlib
 import os
-import platform
 from pathlib import Path
 
 import yaml
@@ -19,33 +18,6 @@ class WorkingDirectory(contextlib.ContextDecorator):
         os.chdir(self.cwd)
 
 
-def is_writeable(dir, test=False):
-    # Return True if directory has write permissions, test opening a file with write permissions if test=True
-    if not test:
-        return os.access(dir, os.W_OK)  # possible issues on Windows
-    file = Path(dir) / 'tmp.txt'
-    try:
-        with open(file, 'w'):  # open file with write permissions
-            pass
-        file.unlink()  # remove file
-        return True
-    except OSError:
-        return False
-
-
-def user_config_dir(dir='Ultralytics', env_var='YOLOV5_CONFIG_DIR'):
-    # Return path of user configuration directory. Prefer environment variable if exists. Make dir if required.
-    env = os.getenv(env_var)
-    if env:
-        path = Path(env)  # use environment variable
-    else:
-        cfg = {'Windows': 'AppData/Roaming', 'Linux': '.config', 'Darwin': 'Library/Application Support'}  # 3 OS dirs
-        path = Path.home() / cfg.get(platform.system(), '')  # OS-specific config dir
-        path = (path if is_writeable(path) else Path('/tmp')) / dir  # GCP and AWS lambda fix, only /tmp is writeable
-    path.mkdir(exist_ok=True)  # make if required
-    return path
-
-
 def increment_path(path, exist_ok=False, sep='', mkdir=False):
     """
     Increment file or directory path, i.e. runs/exp --> runs/exp{sep}2, runs/exp{sep}3, ... etc.