titleDetails implemented on DashCanvasView and DashContainerView

[cnrudd]

DashCanvasView and DashContainerView components now have a public @bindable titleDetails
property on their models to support displaying additional information in the title bar of these
components. titleDetails is not persisted, and is expected to be set programmatically by the
application as needed.

See corresponding Toolbox branch/PR if you want to test: xh/toolbox#781

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• Caught up with develop branch as of last change.
• Added CHANGELOG entry.
• Reviewed for breaking changes, added breaking-change label + CHANGELOG if so: NOT a BREAKING CHANGE
• Updated doc comments / prop-types, or determined not required.
• Reviewed and tested on Mobile: not required.
• Created Toolbox branch: titleDetails implemented on DashCanvasView and DashContainerView toolbox#781

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