Add a progress bar during datasource fresh & after other long refresh actions

Hi

It would be really helpful to have a progress bar displayed when long operations such as a force refresh are being performed. Currently RDM "freezes" until the refresh completes which can be 30+ seconds. There is no visual indicator that a refresh is in progress and users need to keep clicking on items to determine if RDM is ready to use again.

We are using RDM v12.6.8 & 12.9.5 with DVLS 4.6.1 and both have the same issue.

Brenden