[development] RTBC is now "reviewed & tested by the community"

[Nedjo Rogers]

This new status name seems like a good idea. Let's monitor e.g. whether the 
new status should leads to a lower threshold than RTBC did.. The new status 
still needs to meet the need for core committers to have a meaningful list 
of fully reviewed and refined patches.

In future, if needed, we could consider e.g. additional status options for 
expert review to cover that minority of issues that need an extra level of 
review by a maintainer or other developer with recognized applicable 
expertise.

Nedjo