FR: Save reminder message

[ignaciogros]

@Rafav's suggestion: Add a "You should save your work" message after 10 minutes without saving. Include a "Don't show this message again" checkbox.

Pablo Nimo's idea: The message could include a "Save now" button.

This will be in eXe until the autosave functionality works.

[ignaciogros]

@Rafav or @JuanCasanovaSdweb: Could you test that, please?

@jrfern: There are some new strings (you can change them in eXeToolbar.js if needed).

Explanation:

After 10 minutes without saving, a warning message is shown:

You've been working for a long time without saving.

Do you want to save now?

You can also hide the message until the next time you open eXe:

Hide until the application is closed