Additional information for GC status (`riak-cs-admin gc status`)

[ksauzz]

GC state, running, idle, pause, is unclear for Riak CS user.
So 'riak-cs gc status' should include additional fields current state, and also elapsed time.

[shino]

Do you want to show status atoms as is?
Currently status atoms are converted to natual language [1].

Nonetheless, there are space to refine the command, I want some fields, too :)

• the number of active workers
• the epoch of currently processing riak-cs-gc bucket (because "files left" is not useful for gc_paginated_indexes)

[1] lines from riak_cs_gc_console

print_state(idle) ->
    output("There is no garbage collection in progress");
print_state(fetching_next_batch) ->
    output("A garbage collection batch is in progress");
print_state(feeding_workers) ->
    output("A garbage collection batch is in progress");
print_state(waiting_for_workers) ->
    output("A garbage collection batch is in progress");
print_state(paused) ->
    output("A garbage collection batch is currently paused").

[ksauzz]

oops, I've not read the first line in the output.

[shino]

This is nice issue for enhancement of the command output. So, I changed title.

Any comments are appreciated.

[ksauzz]

We should add time unit of 'Elapsed time of current run'. It's 'seconds'.