Merge branch '844-czech-language' into 'develop'

Add new translations, fix en_GB

Closes #846, #845, and #844

See merge request funkwhale/funkwhale!769

changes/changelog.d/844.enhancement

+Added Czech translation (#844)

changes/changelog.d/845.enhancement

+Added Catalan translation files

changes/changelog.d/846.bugfix

+Added context strings to en_GB translations so that picking the language changes the interface as expected

front/src/locales.js

@@ -8,9 +8,18 @@ export default {
     {
       "code": "en_US",
       "label": "English (United-States)"
-    },{
-      "code": "eo",
-      "label": "Esperanto"
+    },
+    {
+      "code": "en_GB",
+      "label": "English (UK)"
+    },
+    {
+      "code": "ca",
+      "label": "Català"
+    },
+    {
+      "code": "cs",
+      "label": "Čeština"
     },
     {
       "code": "de",