Validate actions during their creation

[despadam]

Description

As seen in issue #1341

Motivation

Method validate() in the JobAction class was never used. All validation was done inside the action's constructor.

Changes:

• Removed method validate() from the JobAction class and all its subclasses.
• There is no longer the need to validate the actions before creating a job. This part has been commented out in the interceptor.
• In fact, there is no longer the need to use job-create.interceptor at all. It has been removed from create in the jobs.controller. The reason for this is that the interceptor was doing two things: Apart from action validation which has already been removed, it was also adding the configuration field in the job instance to be created. However this part is already covered by the instanceAuthorizationJobCreate function in jobs.controller.
• checkAuthenticatedUser has been removed from jobs.controller, as it was never used.
• Before statusUpdate we check whether the configuration file has been updated by comparing the new with the one stored inside the job. However, even if they are different, we still proceed with the update as usual, as all actions have been automatically re-initialized with the new configuration. This is a point to be discussed later.

[sofyalaski]

looks good!