merge-i18n

don't add theme based modifications into `src/assets/i18n/*.json5`
directly. Use a script instead to merge them

```
for langfile in src/themes/ukrepo/assets/i18n/*.json5; do
 f=$(basename $langfile);
 grep : $langfile | while read -r line; do
  key=$(echo $line | sed -e 's/\s*:.*//');
  sed -i -e "/^\s\+$key/s/^\(\s*\).*/\1$line/" src/assets/i18n/$f ;
 done ;
done
```

Note that wiki https://wiki.lyrasis.org/display/DSDOC7x/User+Interface+Customization#UserInterfaceCustomization-CustomizeUIlabelsusingInternationalization(i18n)files
suggests

```
yarn merge-i18n -s src/themes/ukrepo/assets/i18n
```

but that removes comments and the linter was not very happy with the
result either.

src/assets/i18n/cs.json5

@@ -2383,7 +2383,7 @@
   // "home.top-level-communities.help": "Select a community to browse its collections.",
   "home.top-level-communities.help": "Vyberte komunitu a procházejte její kolekce.",
   // "home-page.carousel.ldata.info": "Linguistic Data and NLP Tools",
-  "home-page.carousel.ldata.info": "Lingvistická data a nástroje",
+  "home-page.carousel.ldata.info": "Data a nástroje",
   // "home-page.carousel.ldata.find": "Find",
   "home-page.carousel.ldata.find": "Vyhledávání",
   // "home-page.carousel.ldata.citation-support": "Citation Support (with Persistent IDs)",

src/assets/i18n/en.json5

@@ -1935,7 +1935,7 @@
   "home.top-level-communities.help": "Select a community to browse its collections.",
 
 
-  "home-page.carousel.ldata.info": "Linguistic Data and NLP Tools",
+  "home-page.carousel.ldata.info": "Data and Tools",
 
   "home-page.carousel.ldata.find": "Find",
 

src/themes/ukrepo/assets/i18n/cs.json5

@@ -1,3 +1,3 @@
 {
-  "home-page.carousel.ldata.info" : "Data a nástroje"
+  "home-page.carousel.ldata.info": "Data a nástroje",
 }