Update Croatian date/time formats and a bit more

Changes:

* Updated date and time formats to be better aligned with formats used in Croatia.
* Updated the February abbreviation to contain Unicode "ǉ" (alternative spelling: "lj"), which is a single letter in Croatian and thus inseparable. Using the Unicode character doesn't break the three-letter-abbreviation convention.
* Updated very large number units to have correct unit names.
* Removed the comma from "last_word_connector", because it's not allowed with the "i" connector.