Issue-1422: Load the text domain using the "init" hook

[phillip-hopper]

Fixes this WordPress warning:

PHP Notice: Function _load_textdomain_just_in_time was called incorrectly. Translation loading for the qtranslate domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early. Translations should be loaded at the init action or later.

I removed the comment regarding the user not being authenticated because the user is authenticated when the "init" hook fires.

https://developer.wordpress.org/reference/hooks/init/

Closes #1422

[hirasso]

@herrvigg is qtranslate-xt still maintained? 🙏

[rafaelurben]

@hirasso See #1414 (comment) for the most recent update on this matter.