LP#2056204: support "Form of item" in MARC editor for electronic resources

LP#2056204: support "Form of item" in MARC editor for electronic resources

This patch adds mappings to the Angular and AngularJS MARC editors
so that the "Form" (form of item) fixed field positions in the 006
and 008 fields are recognized and (in the case of the 008) editable
via the "Form" input when the record type is "m" (electronic resources/computer files).

Release-note: Fixes problem where "Form" value could not be saved in MARC editor for electronic resources.

To test
-------
[1] Open a bib record of type 'm' (electronic resource) in the Angular
    MARC editor.
[2] Change the form value with the input labeled "Form".
[3] Note that the corresponding position in the 008 is not updated.
[4] Apply the patch and repeat steps 1-3. This type, the change
    should stick.
[5] Bonus: do the same testing in the AngularJS MARC editor.

Signed-off-by: Galen Charlton <gmc@equinoxOLI.org>
Signed-off-by: Mike Rylander <mrylander@gmail.com>
Signed-off-by: Jane Sandberg <js7389@princeton.edu>