feat: statusbar usage

[Ramilito]

Lets put something in the statusbar for the kubectl_header filetype, not sure what to have there though.
Suggestions?

[Ramilito]

@mosheavni You usually have awesome ideas, what should we put in the statusbar or should we leave it empty?

The winbar is used for the divider + resource + filter, we could do something else buffer/view related?
it could be:

• total/running?
• some other health thing?

We have statusbar available for all buffers, the header is not using anything there either

[Ramilito]

Work started here: #615.
It's disabled by default and we think it should be expanded since right now it's not adding any valuable information to make it worth being enabled by default.

Currently it shows: ready nodes/total nodes cluster CPU usage cluster MEM usage warning events the last hour.

What else can we add/remove? @mosheavni