get_osd_tree incorrectly parsing of ceph tree

[Robert Gildein]

The function get_osd_tree are incorrectly parses data from the
`ceph osd tree --fromat=json` output.

The function searches for host with type==host, but wrongly assumes
that it's contains information about root/rack/row etc.

Sample of current information, where it can be seen that they do not
contain any information about the parents.
```bash
{
  "id": -5,
  "name": "juju-1ea5b4-bug1911006-0",
  "type": "host",
  "type_id": 1,
  "pool_weights": {},
  "children": [1]
}
```

This results in the CrushLocation object being created with the correct
name and id, but the other information is empty.

String representation of Crush Location from example above.
```bash
name: juju-1ea5b4-bug1911006-0 id: -5 host: None rack: None row: None datacenter: None chassis :None root: None
```

[Robert Gildein (rgildein)]

review: https://review.opendev.org/c/openstack/charms.ceph/+/780280

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charms.ceph/+/780280
Committed: https://opendev.org/openstack/charms.ceph/commit/5a6fbb88fd7e5bc444957c48263a1ee92bf80d2d
Submitter: "Zuul (22348)"
Branch: master

commit 5a6fbb88fd7e5bc444957c48263a1ee92bf80d2d
Author: Robert Gildein <email address hidden>
Date: Fri Mar 12 16:20:43 2021 +0100

    Fix parsing information from ceph tree output

    Add helper functions to parse information from the ceph tree and
    fix creating CrushLocation object in get_osd_tree function.

    Closes-Bug: #1918721
    Change-Id: I59c742e594042ad527e71c88404999459f0373c2