Bug 28839: Better texts in stage MARC for import

Bug 28839: Better texts in stage MARC for import

Tool stage MARC for import is /cgi-bin/koha/tools/stage-marc-import.pl.
Its form contains texts in legends, labels, hints.

I feel like :
Labels are sometimes too long, showing them on multilines, like "Modify record using the following template". Long texts should be in legend or hint.
Legend are sometimes contains redundant text, like "Stage records into the reservoir".
Section beginning with "Comments about this file" is missing a legend, it looks like it is part of the upper section for profile.

Also lengends should be driving the user, that is why optional parts
contains a legend with "?".

Test plan :
Compare texts in page without and with patch

Signed-off-by: Barbara Johnson <barbara.johnson@bedfordtx.gov>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Bug 28839: (QA follow-up) Fix tabs/indentation in code paragraph

QA tools complained about a tab char. Cleaned up the template paragraph
it pointed out, removing tabs and correcting indentation.

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