Lee Hinman 5af66d79ef
Add SLM support to xpack usage and info APIs (#48149)
* Add SLM support to xpack usage and info APIs

This is a backport of #48096

This adds the missing xpack usage and info information into the
`/_xpack` and `/_xpack/usage` APIs. The output now looks like:

```
GET /_xpack/usage
{
  ...
  "slm" : {
    "available" : true,
    "enabled" : true,
    "policy_count" : 1,
    "policy_stats" : {
      "retention_runs" : 0,
      ...
    }
  }
```

and

```
GET /_xpack
{
  ...
  "features" : {
    ...
    "slm" : {
      "available" : true,
      "enabled" : true
    },
    ...
  }
}
```

Relates to #43663

* Fix missing license
2019-10-16 21:06:27 -06:00
..