Implement operator metric registry

Conflicts:
	exec/java-exec/src/main/java/org/apache/drill/exec/server/rest/ProfileWrapper.java

added hash table metricdef and fixed.

Conflicts:
	exec/java-exec/src/main/java/org/apache/drill/exec/server/rest/ProfileWrapper.java

display metrics in own table

sort fragments, better column names

Conflicts:
	exec/java-exec/src/main/java/org/apache/drill/exec/server/rest/ProfileWrapper.java

add missing waitnanos to senderstats

massive blob of changes