To make configuration values available to the client (see #3568) we need another API endpoint to read and browse config values.

• GET /ghost/api/v0.1/configuration/: all available config values
• GET /ghost/api/v0.1/configuration/<config-name>: one value, identified by config-name

Response format:

{
    configuration: [{
        key:<config-name>,
        value:<config-value>
    }]
}

The configuration endpoint should only return a subset of available config values:

• filestorage (boolean from config.env.fileStorage)
• apps (boolean from config.env.apps)
• version (string, semver from packages.json)
• environment (string from NODE_ENV)
• database (string from config.env.database.client)
• mail (sring from config.env.mail.transport)

Every authenticated user is allowed to read and browse these values.