Add `operations` functionality

[cjellick]

The design dicussion around this yielded the following:

• There are three entities involved here:

  • jobs
  • cronJobs
  • operations
  • jobTemplates

• A job is something ran once during an acorn deployment. The acorn might say deploy a mysql container and run this job (at deploy time) to set the root password and insert some data in it.

• A cronJob...is a job that runs on a cron instead of just once.

• An operation is a description of extra functionality available to a deployed instance of that acorn like backup and restore.

• A jobTemplate can be used in the definition of any of the above. It has the core definition of what will be ran. Each of the types can augment a template with their own fields. cronJob will have a cronSchedule field. Operation will define additional parmaters that the user can specify when they invoke the operation via the cli.

[cjellick]

Addition from @cloudnautique

Provide a way to define a job container that can run on demand(I'd like to stand up an instance to copy out a backup file for instance.).

I'm going to use this issue to encapsulate that ask. We'll need to get to the next level of definition for this