Instance Metadata add tags object/dict

Hi,
so I've noticed that you've implemented tags in the instance metadata as a list.

```
curl -s -H Metadata:true --noproxy "*" "http://169.254.169.254/metadata/instance?api-version=2021-02-01" | jq
[...]
"tagsList": [
{
"name": "TagName1",
"value": "Value1"
},
{
"name": "TagName2",
"value": "Value2"
}
],
[...]

```
But the tags are a dictionary, not a list because the names are unique. You can use to represent it more clearly:

```
"tagsdict": {
"TagName1": "Value1",
"Tagname2": "Value2"
}
```

If it were a "real" list in your datastructure in backend you would be able to duplicate keys. As in have same name with different values.

```
{
"compute": {
"tagsList": [
{
"name": "TagName1",
"value": "Value1"
},
{
"name": "TagName1",
"value": "Value3"
},
{
"name": "Tagname2",
"value": "Value2"
}
]
}
}
```

I would like to see a dictionary implemented so that it reflects the data structure of the backend (no duplicated keys allowed).

Greetings
Klaas

Start by locating the Azure instance metadata specification for the `/metadata/instance` endpoint and its `tagsList` response object. Compare the documented response with the requested dictionary shape and verify the expected handling of duplicate tag names; done means the specification reflects the backend structure without duplicate keys.

Written by the indexing model from the issue text.