Add gettext support to subscribe page

Requirements

• Filling out the template is required. Any Enhancement request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Descriptive title for this enhancement

Add gettext support to subscribe page

Actual behavior

subscribe page is only in english

Expected behavior

That the page detect the language of the browser and show the correct language, fallback to english as always

Step by step description of new behaviour

1. User connect to subscribe page
2. browser show page in his own language

Benefits

Help the user when registering an account

Possible Drawbacks

more code to detect browser

Applicable Issues

user friendliness