Add an option to delay running scenarios after application starts

[ohuu]

Currently Cardamon will immediately start the metric loggers and scenarios after running all the processes to start the application. Some of these processes may require a minimum start/warm up time (e.g. docker containers may need some time to start up).

We should add an option to the processes in the config for specifying a minimum wait time after starting a processes before continuing.

Proposed Change

[[processes]]
type = "baremetal"
name = "server"      # Required
command = "yarn dev" # Required
wait = 5      # <---- number of seconds to wait after starting this process