This validation makes sure that the s3_upload_bucket and the
s3_backup_bucket have different values. The backup bucket is
allowed to be a subfolder of the upload bucket. The other way
around is forbidden because the backup system searches by
prefix and would return all files stored within the backup
bucket and its subfolders.
This change-set allows setting different defaults for different locales.
It also:
- Adds extensive testing around site setting validation
- raises deprecation error if site setting has the default property based on env
- relocated site settings for dev and tests in the initializer
- deprecated client_setting in the site setting's loading process
- ensure it raises when a enum site setting being set
- default_locale is promoted to `required` category.
- fixes incorrect default setting and validation
- fixes ensure type check for site settings
- creates a benchmark for site setting
- sets reasonable defaults for Chinese
