feat(MOS): support OpenMedia's hot standby

[olzzon]

About the Contributor

This PR is made on behalf of BBC

Type of Contribution

This is a Feature

Current Behavior

Currently the Primary and Secondary MOS connection are expected to be online at the same time.

New Behavior

OpenMedia treats the Secondary server as a Hot Standby, so it's not connected while Primary server is connected.
To handle this, a "Hot Spare" option is added in settings to the Secondary server.

When hot spare is activated, status messages are:

• GOOD - When running on Primary, the status of Secondary is ignored.
• GOOD - When running on Secondary the status of Primary is is ignored.
• BAD - If neither Primary or Secondary is connected.

Testing Instructions

Connect MOS gateway to a 2 server OpenMedia setup.

Time Frame

We intend to finish the development on this feature in two weeks time.

Other Information

Status

• PR is ready to be reviewed.
• The functionality has been tested by the author.
• Relevant unit tests has been added / updated.
• Relevant documentation (code comments, system documentation) has been added / updated.