add hr-HR (Croatian) localization for geckium

[weeniemount]

title. adds the Croatian language to the locale folder and adds it to chrome.manifest. also, if there are any inaccuracies, broken stuff, or untranslated strings, please comment about it

[angelbruni]

I will verify this as soon as I can.

At the moment, the credits screen is dedicated to only those who developed and privately tested Geckium, and is not being updated, I only updated it twice to add https://github.com/MrOtherGuy/fx-autoconfig (which loads Geckium) and a private tester which I had forgotten to add (oops...).
There's nothing to worry about though, in Geckium releases, in the description it mentions anyone who have contributed to the release and in https://github.com/angelbruni/Geckium/graphs/contributors it shows everyone who contributed and what they contributed with.

[weeniemount]

sorry i actually meant to delete the am i allowed to add myself as i changed my mind

[angelbruni]

Don't worry, it's good to get clarified about things!

[angelbruni]

Thank you very much!