Bug 34549: Strip non-XML chars during TransformHtmlToMarc

Bug 34549: Strip non-XML chars during TransformHtmlToMarc

This patch strips non-XML characters from inputs during
TransformHtmlToMarc.

To test:
0. Apply patch
1. koha-plack --restart kohadev
2. Go to http://localhost:8081/cgi-bin/koha/cataloguing/addbiblio.pl
3. Fill out record and use the text from "Text file containing control characters"
as the title
4. Click Save
5. Note that your record displays without any warnings like the following:
Error: invalid data, cannot decode metadata object
parser error : PCDATA invalid Char value 27

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
[EDIT] Squashed the tidy patch. Still needed a few spaces to satisfy qa tools.
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>