WebSubmit: make access-control role dependant

• Changes the access-control of the submission interfaces to use WebAccess roles and authorized actions more consistantly.
  
  For example, this will make it possible to allow access to the submission interface for users that are not logged in. (so called 'guest' users).

• Ensures that submission pipelines are public for logged in users unless a WebAccess authentication rule says otherwise. Guest users needs a specific rule to get access to submissions.

• Improves the steps of the submission interfaces to only show submission pipelines and options authorised to the current user.

• Changes the interface of a specific submission pipeline to automatically select the category if there is only one category defined for a certain submission type.

• Removes some hard-coded checks to see if the user is logged in.

• Adds a check to the default WebSubmit functions that handles sending of emails to submitters which makes sure there is any emails to send to.
  
  NOTE: Still, if guest submission is activated, it is important to take extra care when dealing with submitters email during the submission workflow.

• Adds a hook for the 'access' parameter that automatically generates a value for it if it should not have one. Useful when you want users to directly access a submission form without going through all the steps of the category and submission form selection interface.

• Changes the automatically generated URL to approve incoming submission from "?key" to "?access=key".

• Also changes the way approve.py parses the URL to accomodate this change.

• Moves database calls in approve.py to websubmit_dblayer.

• Adds a DEMO case for guest submission, as well as a web test, and amends the web tests for journal submission.