Create options structs to override defaults #94
Description
The orch package defines several types that use default "magic" constants. For example, Watcher defines a constant for the size of its buffered channels. These types should expose options structs that can be passed into their constructors and allow these values to be overridden. They should continue to use sane defaults when no value is specified.
This issue would be a good precursor to #54, since these timeouts should be configurable. This will need to define options for:
- Controller
- Watcher
The Controller should probably accept and proxy any options for the executor, queue and other non-exported types.