Until now it was only used in ERP5Catalog where the expression property is
`expression` for both Python Script and SQL Method but this is also needed
for ERP5Workflow `guard_expression` and `variable_expression`.

TODO:
  - state.getAvailableTransitionList()
  - state.executeTransition()
  - state.getWorkflowHistory()
  - state.undoTransition()
=> erp5_configurator_standard:testStandardConfigurationWorkflow

* Rename WorkflowConfigurator PropertySheet to ConfiguratorWorkflow.
* Add ConfiguratorWorkflowTransition PropertySheet for transition_form_id.
  => Should it be moved to standard 'action' instead?

ERP5Workflow: WorkflowScript_view: Pull changes from PythonScript_view (This fixes editor field which was using Ace).

Workflow Script context must be created before execution. Otherwise Workflow
Script cannot call other Workflow Scripts.

Ignore for now the differences between ERP5Workflow implemented for Configurator
a long time ago and "new" ERP5Workflow.

Work done by Wenjie Zheng, Isabelle Vallet and Sebastien Robin.

See merge request !1275

- this action relies on paged.js library for pagination

Don't log and fix a few resource warnings

See merge request nexedi/erp5!1307

Add missing field, used in testFloatFieldStep