Removed redundant make install-user option.
Beefed up ShellHelper.make_dir .

Takes extra arguments for creating parent directories if required and
also check if the dir already exists.
Fix typo in repobuddy/tests/list.md
Include the .config files under repobuddy/tests/configs.

Add the client config files under repobuddy/tests/configs as part of the
resources.
Implement few of the client_info tests.

Implement the following client_info test cases:
- test_read_nonexistent_file
- test_read_without_permissions
- test_read_malformed_file