Update docs on vSphere hardware requirements

[Amit-PivotalLabs]

Currently, it says a minimal install requires 48GB, and a proof-of-concept install requires 128GB. Those numbers are off by 1-2 orders of magnitude. Also "minimal" and "proof-of-concept" are hard to distinguish. Suggestions:

• in each use case, differentiate between the resources needed for the platform and the resources allocated for apps running on it.
• give some indication of some of the potential tradeoffs (e.g. BOSH needs x cores minimum, but if you deploy with y cores, you can provision the CF cluster much faster)
• cover more uses cases: absolute minimum (1-5GB, this strategy not included in OSS docs), minimal HA deployment, sizable production deployment for 100s-1000s of users running 1000s-100000s of app containers.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. You can view the current status of your issue at: https://www.pivotaltracker.com/story/show/110891084.

[Amit-PivotalLabs]

Turns out this is too hard to document succinctly, as there are too many use cases for Cloud Foundry. I assume users can reach out on multiple community channels for guidance with provisioning hardware and resources for their particular use cases.