Enhance handling of response warnings

[vpnachev]

What would you like to be added:
Improve how are warnings on shoot operation shown in the dashboard:

I am facing the following challenges with the warnings how are they shown today

1. They hide various buttons and info boxes blocking operation with the shoot until the warning are closed.
2. The warnings have to be closed one by one.
3. When navigating away from the shoot page, the warnings are not closed - for example, if I switch to the Secrets page, the warnings are still shown.

I would like to ask for the following:

1. It would be nice to warnings to be shown in a way that they do not obscure other text boxes and buttons in the dashboard.
2. A single button to close all of them when there is more than one warning shown.
3. When navigating away from the shoot page, the warnings to be automatically closed.

I am not sure if this is possible, but it would be nice the dashboard to not show again a warning that has been recently closed, e.g. If I have closed a warning for not rotated SSH key pair for cluster foo/bar in the last 12 hours there is no need the dashboard to show this warning again just for the foo/bar cluster, but If they same warning is fired for another cluster, they it still should be shown.

Why is this needed: