Add support for feature flags

[thewahome]

Is your feature request related to a problem? Please describe. To have a chance to preview new features to a limited set of users, or have the chance to remove a feature from public use, we should use feature flags.

For instance, we can release the header in preview so that we receive feedback about it. Or have two headers and show each to different users. Similar case for resource explorer and other major features that are in development.

Describe the solution you'd like Connect the configurations to azure so that we can turn things on and off.

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context Add any other context or screenshots about the feature request here.

[ddyett]

this is agreed work engineering will drive. moving off PM. Blocked on understanding cost.

[gavinbarron]

@thewahome I'm in fact finding mode on this at the moment looking into what internal tooling there is which we could apply to this.