Add out-of-the-box operations for use in custom workflows

[Roberto Longobardi]

With the addition of custom workflows on any Trac resource, there comes the ability to also define custom operations to be performed along with workflow state transitions.

The TracGenericWorkflow plugin comes with no out-of-the-box operation, and the TestManager plugin only defines a sample operation.

Implement a basic set of custom operations to be used in custom workflows:

• "Assign to": only usable with objects that have an "owner" field, allows for assigning an object to some other User.
• "Notify": sends a mail to the specified Trac Users, or to a set of specified mail addresses. Optionally allow for specifying the mail subject, and for substituting the object's fields into the subject text.

Add other desired operations as comments to this ticket.

[Roberto Longobardi]

Implemented in 1.3.11.

Refer to the wiki page for help on using these operations in your workflows: ​http://trac-hacks.org/wiki/TestManagerForTracPluginWorkflow#Out-of-the-boxoperations