Bug 30142: Remove spaces from ElasticSearch mapping MARC fields

Bug 30142: Remove spaces from ElasticSearch mapping MARC fields

A first step to "validate" the MARC mappings: Remove all whitespace, so
if a user enters "245a " (with a trailing whitespace, which can easily
happen when copy/pasting) we only store "245a" in the DB. This is
neccessary, because the ES indexer will throw an exception in an invalid
MARC mapping.

Test Plan:
* Go to /cgi-bin/koha/admin/searchengine/elasticsearch/mappings.pl
* Go to the Bibliographic Records Tab
* Enter "100 a b c " (notice the whitespaces!) in the first "mapping"
  field
* Scroll down and save
* Go back to the Bibliographic Records Tab
* The spaces are still there

Now apply the patch

* Repeat the above steps
* After saving you should see "100abc" without any spaces in the
  "mapping" field

Sponsored-by: Steiermärkische Landesbibliothek
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>