ExplainPlan with plan as attributes object, use it for BaseStatsCollectorIT

Provide golden files attributes based object for QueryPlan result comparison for all abstract test class BaseStatsCollectorIT that includes tests of all stats collections including:

• NamespaceDisabledStatsCollectorIT
• NamespaceEnabledStatsCollectorIT
• NonTxStatsCollectorIT
• TxStatsCollectorIT

Object based ExplainPlan can be useful for quite precise comparison of individual and relevant plan attributes.