[EXPORTING] Add machine names to workflow states

Updated: Comment #1

Problem/Motivation

Working with actual workflow state values in site glue code is somewhat troublesome. Using integers for identification of states makes little sense in this case, so one end up with a custom reverse map to retrieve a sane name of the current workflow state:

function example_workflow_state_map($sid) {
  $map = array(
    1 => 'creation',
    2 => 'draft',
    3 => 'submitted',
    4 => 'approved',
    5 => 'rejected',
  );
  return $map[$sid];
}

The configured human readable name for states isn't a reliable solution for glue code.

Proposed resolution

One of the following:

1. Convert {workflows}.wid and {workflow_state}.sid to varchar. {workflow_state}'s primary key will then consist of both wid and sid.
2. Add additional machine readable columns to these tables.
3. Make the possible states of a workflow resemble the options of a core 'List' field, (which have code and name).

Working with workflowfield.module it should be possible to use the field's value directly as state:

function example_node_update($node) {
  if ($node->field_workflow_state[LANGUAGE_NONE][0]['value'] === 'draft') {
    …
  }
}

Remaining tasks

- Discussion, decision, implementation. 7.x-2.x? 7.x-3.x? 8.x-1.x? 8.x-2.x? OMG 9.x-1.x?
- Make the Workflow State a true, named, exportable entity, and change the current Admin UI to a more Entity-like screen.

User interface changes

None.

API changes

…