deposit: refactoring bug fixes

• Fixes several JavaScript issues introduced during refactoring of assets as well as dynamic field lists.

• Fixes tag template issue in field lists.

• Fixes issue when appending new elements to field lists.

• Fixes typo in message variable names.

• Fixes uninitialized variables due to strict mode.

• Removes Invenio CKEditor configuration as this is configured by each textarea field in the data-ckeditor-config attribute.

• Adds SPAN-tag to whitelist of HTML-tags to support MathJax integration in CKEditor.

• NOTE Changes deposit/form.js module to export multiple methods. If your instance templates invokes 'form(configuration)' it must be changed to 'form.init(configuration)'.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>