Bug 26456: Reindent MARC subfield structure template

Bug 26456: Reindent MARC subfield structure template

This patch reindents the MARC subfield structure template.
The only non-whitespace changes where lines were combined or split.

The diff using the '-w' flag to ignore whitespace should
highlight only moved lines.

Test that functionality is unaffected: Administration -> MARC
bibliographic framework -> MARC structure -> Edit subfields..

Test adding, editing, and deleting subfields. Confirm that changes are
saved correctly.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>