client: translations: improve Makefile * Change target `translations` to only be remade if one of the `*.po` files changes. Technically is only directly depends on these files. This looks like a defect in the original upstream Makefile logic. * Add found `*.js` files to the dependencies of the `pot` target, because they are used when creating it. This looks like it was missed when adding the Makefile initially with 0fd572582ab8.

#Name of the application, e.g. displayed at login time
VUE_APP_TITLE=Waterway Monitoring system

#Backend URL
VUE_APP_API_URL=/api/
VUE_BACKEND_API_URL=http://gemma_backend:8000

#URL of secondary logo
VUE_APP_SECONDARY_LOGO_URL=

#Path of vendored images is copied during a webpack build
VUE_APP_VENDOR_IMG_PATH=