[Monitoring] Refactor monitoring top nav

[chrisronline]

We currently have a custom top nav that should be resolved with newer EUI and Kibana components and services, specifically the new breadcrumb service (#25884) and an EUI date picker (elastic/eui#1351)

[elasticmachine]

Pinging @elastic/stack-monitoring

[cachedout]

Moved to 7.1 in Stack Monitoring project.

[chrisronline]

This work will most likely go into this effort: #34566

[chrisronline]

@igoristic Will this be done with the client side part of NP migration?

[igoristic]

@chrisronline It won't since we're not doing the full React cutover as part of the NP migration anymore. We're kinda stuck with kbn-top-nav directive for now, since we're migrating with angular. Luckily it will be supported in the NP via createTopNavDirective and createTopNavHelper, so we don't have to do it ourselves. We can still use EuiSuperDatePicker if we really want to, but then we'd have to write our own URL/state-management logic (kinda what GlobalState does today). I would rather leave this for when we "re-write" our app to be 100% React, then we can use the context API to handle this with ease