feat: Implement Scheduler Reference Architecture

This change implements the parts of the Datacenter Scheduling Reference
Architecture as published in SC18.

This commit consists of changes to the database schema such as:

- **Removal of `parallelizability` column in `Task`**
  This field was not used by the simulator and we opted to use a field
  describing the amount of cores the task can run on instead.
- **Removal of `task_id` column in `MachineState`**
  This field did not make sense anymore now that a machine can run
  multiple tasks. Fortunately, this field is not used in the frontend.

1 files changed, 0 insertions, 27 deletions

diff --git a/opendc-simulator b/opendc-simulator
-Subproject 8666a78b86a40c1d8dab28dd18e841318c01f97
+Subproject b4c7f4007ee8890ff25b0fcad4cd650cb0ef4f9