Removes Dapr placement server management

[philliphoff]

Gets Tye out of the business of creating Dapr placement services, as most applications can use the one provided by the standard Dapr initialization (e.g. via dapr init) and that's what dapr assumes when running sidecars unless otherwise directed. (If no placement service was running, just spinning one up as Tye was previously doing isn't sufficient due to dependencies on a properly configured state store.) Maintains the ability to have Dapr sidecars use a different port via placement-port. The Dapr extension will check whether Dapr has been initialized (e.g. via dapr --version) and fails if not, as a further hint to the user that something is amiss.

NOTE: The placement service is required only for applications using Dapr actors. Applications using other Dapr features need not have it running.

Resolves #1175
Resolves #1177