This dev related feature implements partial import of language sentences without tempering the server/data directory, which causes issues with git.

• A new config/env variable is defined: CV_IMPORT_LANGUAGES. It is only used when CV_IMPORT_SENTENCES is set to true
• It keeps a comma delimited list of language codes, like "en,de,tr"
• Only the intersection of the server/data directory contents and this list gets imported. Thus, any language code that does not exist in the directory will be filtered out.
• If it is not defined or set to empty string, all languages in the server/data directory will be imported.

Ex: You want to work on some Turkic languages and set in config.json:

"IMPORT_SENTENCES": true,
"IMPORT_LANGUAGES"="tr,bas,xyz",

and/or in .env-local-docker:

CV_IMPORT_SENTENCES="true"
CV_IMPORT_LANGUAGES="tr,bas,xyz"

only tr and bas locales gets imported.

If merged, I can add related info into DEVELOPMENT.md file...