Naming of datasource in Grafana

There’s a bit of an issue with our datasource configuration in Grafana. The correct config for the v1.0.0 datasource is actually this:
```
---
datasources:
- name: Pyroscope
type: 'phlare'
url: http://pyroscope:4040
jsonData:
backendType: 'phlare'
```

^ note how both `type` and `backendType` are set to `phlare`. It doesn't work if I set `type` to `pyroscope`. If I set `backendType` to `pyroscope`, that actually makes it work with OG pyroscope.

This leads to confusion among users, e.g [look at this conversation in slack](https://pyroscope.slack.com/archives/C01FJRYENPQ/p1693440546441119) (visit [pyroscope.io/slack](https://pyroscope.io/slack) to join that slack).

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We need to fix both of these. We discussed the first one (`type`) in the past, although I couldn't find an issue (@aocenas — feel free to add it here if there is one). If I remember correctly, the fix is not straightforward, but at least it's possible.

The `backendType` is trickier because if you set `backendType` to `pyroscope` that actually already means something (`og pyroscope`) and so that makes everything more confusing and complex. Best solution I can come up with right now is to not advertise `backendType` setting in our docs at all and let Grafana self-select the right type.

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cc @aocenas @Rperry2174 — curious what you guys think