Provide proper documentation for CORTX prerequisites

[gregnsk]

For example, requirement for RoCE and TCP connectivity.
@ipoddubnyy - please add other known restrictions

[johnbent]

More info from @ipoddubnyy email:
"This is probably should be added to some sort of quick install or user guide - whatever we are using to tell the customer how to install and configure the system."
and
"We had a discussion this morning about the case when someone downloads our open-source install and installs it on a system that has non-Mellanox InfiniBand HCA (for example, Intel OmniPath). In this case, our stack won't work as of today. It will work with other non-Mellanox high-speed Ethernet cards.

Could we have a message (probably as part of the announcement) that we only support RoCE and TCP connectivity? This would eliminate non-Mellanox IB.

In future we can add this support, if needed."

Thanks @ipoddubnyy and @gregnsk !

[Saumya-Sunder]

Hey @ipoddubnyy,
Can you specify what other non-Mellanox high-speed Ethernet cards support our stack? I want to document the list of supported cards.
Thanks,
Saumya Sunder

[ipoddubnyy]

Any Ethernet card. It does not have to be high-speed. Someone can decide to use a 1 GbE card and it will work.
I believe we need to explicitly document that Intel's OmniPath cards are not supported (since those will be "non-Mellanox IB card").

[Saumya-Sunder]

Done, and closing this issue as it is resolved.