Rework ScheduledTask function selection

[scott-taubman]

The function selection for creating a ScheduledTask needs to be reworked in a few ways:

• The initial selection should happen before you get over to the screen where you enter the schedule and parameters. That would let us simplify the parameter input rendering since we'd have a single, known function (or workflow) to render the parameters of and wouldn't need to do the dynamic reloading thing. This could work similar to the workflow creation, where you get a modal to enter some initial information (the thing you are scheduling) and then click "Next" to get to the scheduling screen.
• The function selection should either be tiered, where you pick a package first and then a function within that package, or clearly show what package a function belongs to in the selection list so that it is possible to differentiate between functions with the same name that are in different packages. We could possibly have both, where you can optionally filter by package first, then function.
• It needs to be possible to select a workflow to schedule rather than a function. This might make a case against the tiered selection described above and more in favor of just clearly showing what package a function belongs to, since workflows will need to show up in the same list and are not associated with a package.

Some thought will need to be put into the design of this, but at the end of the day it needs to be clear and easy to find the function or workflow the user is trying to schedule.

[scott-taubman]

Requires #234 be completed first.