Bug 8954: Make languages list in advanced search translatable (revision 1)

Bug 8954: Make languages list in advanced search translatable (revision 1)

In opac-search.pl and search.pl, this patch moves the $lang variable from the end to the begining of the script, and use it as a parameter for getAllLanguages.
In Languages.pm, getAllLanguages function is modified :
- if no parameter is passed to the function, it returns english languages names
- if a $lang parameter conforming to RFC4646 syntax is passed :
-- the function returns languages names translated in $lang if possible
-- if a language name is not translated in $lang in database, the function returns english language name
To test, set your opac and staff interface in english and in other languages and check search.pl and opac-search.pl :
- If language names in your languages_description table are translated in the same language you use for your GUI, the language names in dropdown list will be translated in this language (+native name).
- If your GUI is in english, or in a language into whitch languages names are not translated in languages_description, the dropdown list will stay in english (+native name).

Signed-off-by: Marc Veron <veron@veron.ch>
Patch behaves as expected.

With Opac language set to French I got all languages with French language name.
With German (de-DE), I got only a few with German language names (and all other with English ones),
this was due to missing entries for de-DE in table language_descriptions.
This behaviour is consistent with the description above.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Tested language list in OPAC and staff advanced search is translated
properly after applying the patch. Checked that language switcher still
works like it should.

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Fixed typo in POD.