Clean up settings page

[bwalkerl]

• Re-add s3 credential provider chain check that was removed by mistake in Implemented new check class for cloud storage connection and added to settings page. #729 - checks whether the it is safe to enable the use credential provider chain setting. This has been converted to use the check API and only provides information relevant to the use of a single setting so is only required on settings page when not checked. The results of this check have been also updated to INFO and lang strings made more descriptive.
• Move connection status to the above where the client settings are set, so status is visible when updating client settings.
• Cherry-pick Issue #633: Move preferexternal setting #641

[petersistrom]

Code looks good, just a couple of comments above