i18n: Add greek translations

[f1234k]

Describe your PR, what does it fix/add?

Add greek translation.

Is there anything you want to mention? (unchecked code, possible bugs, found problems, breaking compatibility, etc.)

Nope.

Is it ready for merging, or does it need work?

Ready for merging.

[vaxerski]

ai, please recheck

[github-actions]

AI translation check result:

Translation check not ok

• TXT_KEY_PERMISSION_REQUEST_UNKNOWN (el_GR): starts with Latin "Mια" (ASCII M) instead of Greek "Μια".
• TXT_KEY_PERMISSION_REQUEST_SCREENCOPY (el_GR): starts with Latin "Mια" (ASCII M) instead of Greek "Μια".
• TXT_KEY_PERMISSION_REQUEST_PLUGIN (el_GR): starts with Latin "Mια" (ASCII M) instead of Greek "Μια".
• TXT_KEY_PERMISSION_DENY (el_GR): "Aρνούμαι" starts with Latin "A" instead of Greek "Α" (and button label/form may be better as "Άρνηση").
• TXT_KEY_NOTIF_FAILED_ASSETS (el_GR): uses incorrect word "πακετά" (nonsense/grammatically wrong). Needs a correct term (e.g. "πακέτου/παραλήπτη πακέτου/πακεταρίσματος" or "πακεταρίσματος της διανομής σας") and general grammar tuning.
• TXT_KEY_NOTIF_INVALID_MONITOR_LAYOUT (el_GR): missing space due to literal concatenation ("... για" + "περισσότερα" -> "γιαπερισσότερα").
• TXT_KEY_NOTIF_MONITOR_AUTO_SCALE (el_GR): "Μη έγκυρh" uses Latin 'h' instead of Greek 'η' and should be "Μη έγκυρη".
• TXT_KEY_NOTIF_FAILED_TO_LOAD_PLUGIN (el_GR): left in English ("Failed to load plugin {name}: {error}") instead of Greek.

Please note this check is a guideline, not a hard requirement. It is here to help you translate. If you disagree with some points, just state that. Any typos should be fixed.

[f1234k]

ai, please recheck

@vaxerski most of the issues mentioned by AI should be fixed now. The TXT_KEY_NOTIF_FAILED_ASSETS notification is bogus.

[vaxerski]

okay, thanks!

[vaxerski]

clang-format pls