Create a sys.queries table

We should create a sys.queries table that provides a clusterwide view of active queries. It could include the following columns:

queryid, user, sql, current status, number of nodes involved, number of total fragments, number of fragments completed, start time

This should be a pretty straightforward task as we should be able to leverage the capabilities around required affinity. A great model to build off of are the sys.memory and sys.threads tables.