Merge Overview and Traffic tab information into one

[lucasponce]

With the refactor of the "overview" tab I think the "traffic" tab is a little bit redundant as the overview graph is showing the same information as the "traffic" tab.

Also, with the refactoring of the metrics #3948 that tab will be more "executive" allowing user to focus on "which metric" is the important for my scenario, and allow the user to expand it to get into more details (and correlate with other signals as traces).

Thinking on the next steps, Kiali will likely increasing the focused on the Sidecar/Envoy metrics as it happens by default:

So, I propose to remove the Traffic tab and consolidate this info into the overview (if we miss any info that the minigraph is not showing today).

That will simplify the tabs and contextual menu:

And it will open the door to integrate with other actions (more sidecar oriented or introducing configuration actions in more places).

Another thought is that I guess that "Inbound Metrics" / "Outbound Metrics" could be more meaningful with "Inbound Traffic" / "Outbound Traffic" as it's basically what it is. And "Envoy Metrics" should certainly move to "Envoy Status".
(Here I see the metrics as part of the implementation but the user should use those tabs to get information about traffic and/or sidecar status).

But this a side thought to put more context about this issue.

[lucasponce]

This was discussed and the agreement was to keep the "Traffic" tab as it is as it may be useful to users.
In a future redesign this one could be revisited but closing for now.