docs: p-weave does not provide a service broker

[st3v]

In quite a few places the docs refer to a Weave Cloud Service Broker that creates services. That's not correct. There's no service broker and there are no services included in this tile. Those terms have a very specific meaning in the context of Cloud Foundry (see https://docs.cloudfoundry.org/services/overview.html if you're interested).

What this tile really does is to:

• collocate the Weave Cloud agent on all VMs inside the ERT deployment
• deploy an instance of Prometheus that is configured to scrape the CF API, CF Firehose, and the BOSH API, and forward all of those metrics to Weave Cloud

@stefanprodan + @ngehani: Would you mind clarifying this in the docs? I believe this will also help with your upcoming demos and user validation.

[stefanprodan]

@ngehani the tile name is Weave Cloud for PCF not Weave Cloud Service Broker for PCF

Thanks @st3v for the feedback, @ngehani will address it.