[doc] add Resource-Requirement recommend hardware spec [Future extend best practices doc]

[YanjieGao]

What would you like to be added:
add Resource-Requirement recommend hardware spec []
Why is this needed:
change wiki page
Without this feature, how does the current module work：
work well, but user confused about how to config it
Components that may involve changes:
wiki page of https://github.com/Microsoft/pai/wiki/Resource-Requirement

[squirrelsc]

@YanjieGao I'm not very clear what's expected in this issue? There is resource-requirement page already, is anything needed more?

[hao1939]

Close it, we already have a resource-requirement page.