move server report ext to extensions (#14087)

* move server report ext to extensions

* limit the size of data

* comments

extensions/server-report/src/sql/allocationContention.sql

@@ -0,0 +1,19 @@
+--SQL script to grab allocation contention from histogram
+Use tempdb
+DECLARE @target_data XML;
+SELECT @target_data = CAST(t.target_data AS XML)
+FROM sys.dm_xe_sessions AS s
+JOIN sys.dm_xe_session_targets AS t
+    ON t.event_session_address = s.address
+WHERE s.name = N'PageContention' and t.target_name = N'histogram';
+
+with wait_stats as
+(
+SELECT
+    n.value('(value)[1]','bigint') AS id,
+    n.value('(@count)[1]', 'bigint') AS [Count]
+FROM @target_data.nodes('//HistogramTarget/Slot') AS q(n)
+)
+
+SELECT [dbo].[mapPageType](wait_stats.id), wait_stats.Count
+FROM wait_stats