DRILL-963: Fix Hive test [TestViews.testInfoSchemaWithView()] on Windows
DRILL-964: Allow enabling/disabling storage plugin instance from UI

+ Creating a client per request (to avoid issues with multiple connections).
+ Correcting the links.
+ Searchable result table.
+ Minor UI tweaks.

Squashed commits:
[461182d]
[99a678a]
[2c16c3a]
DRILL-965: Close underlying buffers/channels when FragmentContext is closed.

* Fixes unit test failures due race condition between closing the allocator and last message handling.