This change allows the selection of a specific broker service (or broker tier) by the Router.
The newly added ManualTieredBrokerSelectorStrategy works as follows:
Check for the parameter brokerService in the query context. If this is a valid broker service, use it.
Check if the field defaultManualBrokerService has been set in the strategy. If this is a valid broker service, use it.
Move on to the next strategy
* Druid user permissions apply in the console
* Update index.md
* noting user warning in console page; some minor shuffling
* noting user warning in console page; some minor shuffling 1
* touchups
* link checking fixes
* Updated per suggestions
Kashif Faraz
sthetland
Jonathan Wei
Chi Cao Minh
Gian Merlino