Setup secondary LINGUAS to allow partial install

Prior to release, we will disable languages that don't meet our criteria
(minimum translation > 75%) but we want to keep the languages available
for translation.  LINGUAS lists all languages available.
LINGUAS_INSTALL lists just the languages that will be installed for use
in KiCad.  Right now they are the same content.  This will be changed
prior to v6 release

translation/CMakeLists.txt

@@ -10,7 +10,7 @@ else()
         CACHE PATH "Location of KiCad i18n files." )
 endif()
 
-file(STRINGS pofiles/LINGUAS LANG_ARRAY REGEX "^[^#].*")
+file(STRINGS pofiles/LINGUAS_INSTALL LANG_ARRAY REGEX "^[^#].*")
 
 # Add the commands to translate each language file
 foreach( LANG ${LANG_ARRAY} )

translation/pofiles/LINGUAS_INSTALL

@@ -0,0 +1,36 @@
+# please keep this list sorted alphabetically
+#
+bg
+ca
+cs
+da
+de
+el
+en
+es
+es_MX
+fi
+fr
+hu
+id
+it
+ja
+ko
+lt
+lv
+nl
+no
+pl
+pt
+pt_br
+ro
+ru
+sk
+sl
+sr
+sv
+th
+tr
+vi
+zh_CN
+zh_TW