[Doc'd] Swap usage shoots up with view querying or indexing

• Setup a 7 node cluster,
• RAM (for each physical machine): ~32GB
• create 2 buckets: default (bucket quota: 12000MB per node) and saslbucket (bucket quota: 7000MB per node)
• run a load (with just creates), until the item count hits a mark
• create 2 views over each of the buckets
• Run load that pushes system into DGM, ~80% resident ratio for default, and ~60% resident ratio for saslbucket
• Run queries continuously against the views as the load continues.
  (for e.g.:
  curl -X GET 'http://10.1.3.235:8092/default/_design/d1/_view/v1?startkey=0&stale=ok&limit=1000')
• Noticed the increased swap usage.
• Start a new mixed load on both the buckets (creates, updates, deletes, expires).
• Setup XDCR to another 5 node cluster.
• Continue querying, noticed considerable increase in swap usage.

This behavior is seen with a cluster with views as well (no XDCR involved).