Juju status should be able to use availability zones

[Connor Chamberlain]

This is a wish-list item to improve the functionality of `juju status`.

There are times when it would be useful to quickly see everything deployed in a certain availability zone in Juju. Just like how we can provide `juju status` with nothing, a machine number, an application name, or a unit name, we should be able to provide the name of an availability zone.

Presently, the best way to see a full availability zone is to grep the zone name out of the machine list (`juju machines | grep <zone-name> | grep -v lxd`) then check the status of each metal found in that list (`juju status <machine-num>`). This process is cumbersome and error prone, and we could shorten it to a single step.

[Heather Lanigan (hmlanigan)]

Perhaps the `juju status` filter can be updated to check AZ, as the data is there for juju status output

$ juju status
Model Controller Cloud/Region Version SLA Timestamp
one aws-us-east-1 aws/us-east-1 3.1-beta1.1 unsupported 21:30:15Z

App Version Status Scale Charm Channel Rev Exposed Message
ubuntu 20.04 active 4 ubuntu stable 21 no

Unit Workload Agent Machine Public address Ports Message
ubuntu/0 active idle 0 54.152.162.41
ubuntu/1* active idle 1 35.171.244.225
ubuntu/2 active idle 2 52.202.139.80
ubuntu/3 active idle 3 54.87.140.141

Machine State Address Inst id Base AZ Message
0 started x.x.x.x. i-079c76645f7df4086 ubuntu@20.04 us-east-1a running
1 started x.x.x.x. i-0f4824fd9bb306ec0 ubuntu@20.04 us-east-1f running
2 started x.x.x.x. i-09874cda68f4e16f1 ubuntu@20.04 us-east-1c running
3 started x.x.x.x. i-0cb3134a340e7265e ubuntu@20.04 us-east-1b running

$ juju status us-east-1a
Model Controller Cloud/Region Version SLA Timestamp
one aws-us-east-1 aws/us-east-1 3.1-beta1.1 unsupported 21:30:19Z
Nothing matched specified filter.