Switch from caching estimates to actuals

Support backslashes in DB/schema/table names for permissions checks

Add a few util fns; other minor code tweaks

Record database_id in QueryExecution; record query in Query

Change query perms-set fn to take kwargs for opts

Add query-perms/can-run-query? helper fn 

Add test for updating perms graph from API

Code cleanup and i18n fixes

Better-organized HTTP client used for tests and add full-response option

Use middleware impl for test util fn bind-current-user

Bump Jetty server version

Don't strip insights from response in public links

Merge release 0.31.0 into master

This commit switches to a stream based nippy
compression/serialization. This has the benefit of being able to stop
serialization once the threshold for cache size has been reached.

Fixes #7479

Simplify SparkSQL driver; fix nested query support

BigQuery nested query support

Remove BigQuery driver custom implementation of field->alias