Add KYAML support

KYAML is a strict subset of YAML, which is sort of halfway between YAML
and JSON.  It has the following properties:
* Does not depend on whitespace (easier to text-patch and template).
* Always quotes value strings (no ambiguity aroud things like "no").
* Allows quoted keys, but does not require them, and only quotes them if
  they are not obviously safe (e.g. "no" would always be quoted).
* Always uses {} for structs and maps (no more obscure errors about
  mapping values).
* Always uses [] for lists (no more trying to figure out if a dash
  changes the meaning).
* When printing, it includes a header which makes it clear this is YAML
  and not ill-formed JSON.
* Allows trailing commas
* Allows comments,
* Tries to economize on vertical space by "cuddling" some kinds of
  brackets together.
* Retains comments.

Examples:

A struct:

```yaml
metadata: {
  creationTimestamp: "2024-12-11T00:10:11Z",
  labels: {
    app: "hostnames",
  },
  name: "hostnames",
  namespace: "default",
  resourceVersion: "15231643",
  uid: "f64dbcba-9c58-40b0-bbe7-70495efb5202",
}
```

A list of primitves:

```yaml
ipFamilies: [
  "IPv4",
  "IPv6",
]
```

A list of structs:

```yaml
ports: [{
  port: 80,
  protocol: "TCP",
  targetPort: 80,
}, {
  port: 443,
  protocol: "TCP",
  targetPort: 443,
}]
```

A multi-document stream:

```yaml
---
{
  foo: "bar",
}
---
{
  qux: "zrb",
}
```

Author: thockin

go.mod

@@ -6,4 +6,5 @@ require (
 	github.com/google/go-cmp v0.5.9
 	go.yaml.in/yaml/v2 v2.4.2
 	go.yaml.in/yaml/v3 v3.0.3
+	sigs.k8s.io/randfill v1.0.0
 )

go.sum

@@ -4,5 +4,5 @@ go.yaml.in/yaml/v2 v2.4.2 h1:DzmwEr2rDGHl7lsFgAHxmNz/1NlQ7xLIrlN2h5d1eGI=
 go.yaml.in/yaml/v2 v2.4.2/go.mod h1:081UH+NErpNdqlCXm3TtEran0rJZGxAYx9hb/ELlsPU=
 go.yaml.in/yaml/v3 v3.0.3 h1:bXOww4E/J3f66rav3pX3m8w6jDE4knZjGOw8b5Y6iNE=
 go.yaml.in/yaml/v3 v3.0.3/go.mod h1:tBHosrYAkRZjRAOREWbDnBXUf08JOwYq++0QNwQiWzI=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+sigs.k8s.io/randfill v1.0.0 h1:JfjMILfT8A6RbawdsK2JXGBR5AQVfd+9TbzrlneTyrU=
+sigs.k8s.io/randfill v1.0.0/go.mod h1:XeLlZ/jmk4i1HRopwe7/aU3H5n1zNUcX6TM94b3QxOY=