1)Dspace enhancement, mapping author names to registered users with UI options.2)Keeping UI option to chose autor-user wise Collections where the item can be mapped.

This commit tries to achieve following things:
1)Currently in DSpace, authors are present as just names. They are not mapped to the users registered to DSpace. If an organization wants to track which authors are which users  for a submitted item where multiple authors are there or the submitter is not the author, there is no provision for that. This code would map the authors to the users with name matching. Now basic , first name, last name matching is done. Later it can be extended to add heuristic matchings and or plugging in Authorization control.

The mapped users would be shown in submission work flow DescribeStep by checkboxes. The checked ones would be saved in item metadata as chosen-authors.
All authors mapped as users would be kept as available-authors in item metadata.
2)The collections where the author-mapped-users have got submit authorization, would then be shown in the submission workflow with check boxes. Say AuthorName1 matched User1 and AuthorName2 mapped User2 and User1 has 3 collections where she can submit, 
and User2 has 1 collection where he can submit. The collections would then be shown in DescribeStep as
User1: Col1 [], Col2 [], Col3 [] .
User2: Col4[]. 
Now submitter can chose Col2 and Col4 as the collections where the Item should be mapped.
So those two collection ids would be saved as chosen-collections in Item Metadata.
Upon finishing the item submission , in InstallItem step the item would get mapped to chosen collection. The owning collection logic remains intact.

To achieve this , new dublin core metadata fields are added and they are used in input-form with specific input-types.