Document behaviour of resource in REST API

With the changes from YUNIKORN-1105 a flow on change has been introduced in the REST API: memory is now send in Bytes always and not in Mega Bytes. What used to be 1 is now 1000000.

We need to document the behaviour on how to interpret the Resource values in the REST API:

• memory: bytes
• vcores: milli cores
• other resources: no units