Normalize the Distance dimensions in the same way as done in Quantity

```
$ curl -XPOST http://0.0.0.0:8000/parse --data 'locale=en_GB&text=10kg > 10 gram, 10km > 10 cm' | python -m json.tool

[
{
"body": "10kg",
"start": 0,
"value": {
"value": 10000,
"type": "value",
"unit": "gram"
},
"end": 4,
"dim": "quantity",
"latent": false
},
{
"body": "10 gram",
"start": 7,
"value": {
"value": 10,
"type": "value",
"unit": "gram"
},
"end": 14,
"dim": "quantity",
"latent": false
},
{
"body": "10km",
"start": 16,
"value": {
"value": 10,
"type": "value",
"unit": "kilometre"
},
"end": 20,
"dim": "distance",
"latent": false
},
{
"body": "10 cm",
"start": 23,
"value": {
"value": 10,
"type": "value",
"unit": "centimetre"
},
"end": 28,
"dim": "distance",
"latent": false
}
]
```

Can the Distance dimension be normalized to `centimeter` similar to how the Quantity dimension is normalized to `gram`?

Reproduce the example through the /parse endpoint and compare the Quantity and Distance results. Trace the existing Quantity normalization behavior and the Distance handling, then verify that distance values such as 10km and 10 cm are normalized to the expected centimeter unit.

Written by the indexing model from the issue text.