mgr/telemetry: improve output of `ceph telemetry collection ls`

mgr/telemetry: improve output of `ceph telemetry collection ls`

STATUS column now indicates whether a collection is being reported, and
the reasons why it's not (either the user is not opted-in to this
collection, or its channel is off).

Also, removed the ENROLLED and DEFAULT columns due to potential
confusion they may cause.

In case a user is not opted-in to certain collections, a message will
appear above the table with the missing collections:

    New collections are available:
    ['basic_base', 'basic_mds_metadata', 'crash_base', 'device_base',
    'ident_base', 'perf_perf']
    Run `ceph telemetry on` to opt-in to these collections.

Signed-off-by: Yaarit Hatuka <yaarit@redhat.com>