Check all translation messages present or not - New feature

A new feature that will check all the response messages, mail subjects which have used the `trans` function and check whether a message exists in `resources\lang` folder if not need to show error messages with the list of translations that are not available.

No source files or tests are named. Start by locating uses of the `trans` function and the `resources\lang` directory, then define how response messages and mail subjects will be discovered and how missing translations should be reported; done means the feature identifies every missing message and shows their list.

Written by the indexing model from the issue text.