ERP5Workflow: add variable to avoid multiple call to function and remove successive 'if/continue' for readability

ERP5Workflow: revert more changes (some Property Sheets have been moved to erp5_workflow bt5, they are back to product/ERP5/bootstrap)

- erp5_test_workflow
  *  add testWorklowMixin test case for inheritance purpose,
  *  move testWorklist ERP5 test to portal_component

author: Wenjie Zheng

The item of produced resources must not be reused on consumed resources

in some rare cases, proxy was still alive for unknown reasons,
thus we had troubles to start a new one. some testnodes were failing
randomly because of this

This change solves the error which one gets while trying to access properties
Form for an ERP5 object having one or more of its property of type 'selection'
or 'multiple selection'.
For example: If you try to access property form for any portal_type objects,
you'll get an error : "'select_variable' is not defined". This is because of the
absence of the property 'select_variable' for the property of type multiple selection,
which in case of portal_type object is 'Property Sheet List'.

This is helpful for ERP5 views/forms which displays selection or multiple selection
type object.

ERP5 Subcategory: Remove '_'(underscore) from 'multiple_selection' subcategory in elmentary_type category.

Subcategory 'multiple_selection' has been renamed to 'multiple selection' to maintain consistency.
Earlier, whenever a new StandardCategory object was created with property_type 'multiple selection',
one needed to change the elementary type explicilty to use it to generate property setters and getters.
The example for this can be seen from this commit:
nexedi/erp5@fd738753
After this change, in the view, property type field couldn't recognize the property and displays
(???multiple selection).

Also, everywhere in erp5, list_types do mention 'multiple selction' and not 'multiple_selection'.
So, its better to maintain consistency in naming the subcategory.

Implement an ad-hoc responsive CSS for ERP5.
This CSS is generated with the LESS compiler (http://less2css.org/).

Create new ERP5 launcher, to break compatibility with officejs.
OfficeJS apps will be migrated one by one to the new CSS.