Support active/inactive functionality of supply/resource item

[sanak]

Problem
Related with #17, there seems to be use case that filtering out some supply/resource items is preferable when adding supply/resource item in issue edit view.
Resource item has end date and it is possible to filter out ended items, but that is not so straight forward.

Improvement
Support lock/unlock functionality in supply/resource item like Redmine core's user model.

Alternatives
About the additional attribute name, either of the followings can be used:

• status (integer): Redmine core User/Project models
  • User: STATUS_ANONYMOUS: 0, STATUS_ACTIVE: 1, STATUS_REGISTERED: 2, STATUS_LOCKED: 3
  • Project: STATUS_ACTIVE: 1, STATUS_CLOSED: 5, STATUS_ARCHIVED: 9
• active (boolean): Redmine core Enumeration and CustomFieldEnumeration (used as Key/value list custom field type, checkbox) models
  • Japanese translation is 有効
• locked (boolean): Redmine core Message model (used as Forum post checkbox)

[sanak]

lock/unclock words may be too much for just filtering out some supply/resource items, so I will use active/inactive for this issue.

[sanak]

Well, this changes cause too long supply/resource items list in /projects/{project identifier}/(asset|human)_resource_items views.
Probably, supporting filter by status function like Redmine core /users and /admin/projects views will be necessary, although supporting sort order by position logic will become quite complex.