[SUGGESTION - cosmetic] Consider "spinning wheel" when changing repositories

[mcm1957]

Is your feature request related to a problem? Please describe. no

Describe the solution you'd like When changing the repository sources (i.e. stabl -> latest) and clicking save and exit ioBroker.admin seems to hang. In reality (I guess) it is downloading the new repository data. The time seems to depend on internet speed and system speed.

Please consider to add a "spinning wheel" or soma other indicatio that admin is busi working and the save / exit button has been accepted.

Additional context If this cannot be implemnted with MINIMAL effort, please close the isse. I've written this down as when I changed the repo the first time I aborted the session because I was thinking something went wrong. This abort might cause other troubles. So I think some indication could be good for unexpirienced users. Bute do not spend to much time on this !

[Apollon77]

I like this idea ... also for other "Potentialla longer running actions"