mgr/dashboard: Speed improvements of pool details

mgr/dashboard: Speed improvements of pool details

Now all variables that are shown in a listing that trigger a
more complex render cycle will only be updated if pool properties have
changed and not only the time series data, which isn't shown anymore,
as it can be seen graphically enhanced in the pool listing.

The pool detail component now uses the `onPush` change detection
strategy, to only call `ngOnChanges` if one of the input variables
have changed.

The function that only updates variables if they have changed is
now available through a helper class in order to provide this
useful functionality through out the dashboard.

Fixes: https://tracker.ceph.com/issues/46375
Signed-off-by: Stephan Müller <smueller@suse.com>