Display clusters in front end

## Description

The API is now grouping items into topics.
Please can we display them in a nice way in the UI

You can see this in the call to `/text/match`, e.g.:

```
curl -X 'POST' \
'http://localhost:8000/text/match?include_catalogue_matches=false&is_negate=true' \
-H 'accept: application/json' \
-H 'Content-Type: application/json' \
-d '{
"instruments": [
{

"questions": [
{
"question_text": "Feeling nervous, anxious, or on edge"
},
{
"question_text": "Not being able to stop or control worrying"
}
]
},
{
"questions": [
{
"question_text": "Sentir-se nervoso/a, ansioso/a ou muito tenso/a"
},
{
"question_text": " Não ser capaz de impedir ou de controlar as preocupações"
}
]
}
]
}'
```

```
{
"instruments": [

///... ///
}
],
"clusters": [
{
"cluster_id": 0,
"centroid_id": 0,
"item_ids": [
0,
2
],
"text_description": "Feeling nervous, anxious, or on edge"
},
{
"cluster_id": 1,
"centroid_id": 1,
"item_ids": [
1,
3
],
"text_description": "Not being able to stop or control worrying"
}
]
}
```

## Rationale

Many users have requested this feature.