DRILL-5716: Queue-driven memory allocation
* Creates new core resource management and query queue abstractions.
* Adds queue information to the Protobuf layer.
* Foreman and Planner changes
- Abstracts memory management out to the new resource management layer.
This means deferring generating the physical plan JSON to later in the
process after memory planning.
* Web UI changes
* Adds queue information to the main page and the profile page to each
query.
* Also sorts the list of options displayed in the Web UI.
- Added memory reserve
A new config parameter, exec.queue.memory_reserve_ratio, sets aside a
slice of total memory for operators that do not participate in the
memory assignment process. The default is 20% testing will tell us if
that value should be larger or smaller.
* Additional minor fixes
- Code cleanup.
- Added mechanism to abandon lease release during shutdown.
- Log queue configuration only when the config changes, rather than on
every query.
- Apply Boaz’ option to enforce a minimum memory allocation per
operator.
- Additional logging to help testers see what is happening.
closes #928
